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When I play a FPS with my wireless mouse I feel that the game reacts more slowly than my movements. Is a wireless mouse less reactive than a classic mouse? Is there a loss of performance with wireless mouse? What is the latency of a classic mouse or wireless mouse? How can I test that?

I remember when I tried a wireless mouse years back and it was horrible. It did not feel responsive enough in games. Should I consider buying a wireless mouse if it otherwise seems good?

I need to use a non-Maven project (simply a folder with script files) from a remote hg repo as a resource for my Maven project in git. I need to use those files in my Java code. What is the way to add them to my project it without: - Having to fork a non-maven repo - Having to make that project into Maven project - Having to move either project to a different repo There must be some Maven plugin that lets adding archives to a project but I just cannot google it.

Maven 2 is driving me crazy during the experimentation / quick and dirty mock-up phase of development. I have a pom.xml file that defines the dependencies for the web-app framework I want to use, and I can quickly generate starter projects from that file. However, sometimes I want to link to a 3rd party library that doesn't already have a pom.xml file defined, so rather than create the pom.xml file for the 3rd party lib by hand and install it, and add the dependency to my pom.xml, I would just like to tell Maven: "In addition to my defined dependencies, include any jars that are in /lib too." It seems like this ought to be simple, but if it is, I am missing something. Any pointers on how to do this are greatly appreciated. Short of that, if there is a simple way to point maven to a /lib directory and easily create a pom.xml with all the enclosed jars mapped to a single dependency which I could then name / install and link to in one fell swoop would also suffice.

A private information retrieval (PIR) protocol is a protocol that allows a user to retrieve an item from a server in possession of a database without revealing which item is retrieved. An oblivious transfer (OT) protocol is a type of protocol in which a sender transfers one of the potentially many pieces of information to a receiver, but remains oblivious as to what piece (if any) has been transferred. As the Wikipedia said, PIR is a weaker version of 1-out-of-n oblivious transfer, but I do not really know why is a weaker version.

I am trying to make a taxonomy of the different purposes of some cryptographic protocols. Generally speaking, the purpose of PIR, oblivious transfer and differential privacy--it sounds as if they were invented for the same purpose: "Give me the information I want without learning anything about this information". Can we make the aforementioned generalization?

Let $y(x,\xi)$ be the value at point $x$ of the maximal solution that satisfies the initial condition $y(0)=\xi$. Prove that the domain of $y(\cdot, y(s, \xi))$ is $I-s$, where $I$ is the domain of $y(\cdot ,\xi)$. Prove that for all $s, t$ such that $y(s, \xi)$ and $y(t+s, \xi)$ exist, then $y(t,y(s,\xi))$ also exists and $y(t,y(s,\xi))=y(t+s, \xi)$. If $y$ is a maximal solution and there exists $T>0$ such that $y(0)=y(t)$ and $f(y(0))\neq 0$, then $y$ is a periodic solution and not constant. In the above problem, I'm missing only that in 3., $y$ is defined on $\mathbb R$. I asked about this problem . The user Artem has provided some help in the comments regarding this, but I can't transform it into an answer. I have a theorem that says that if for all $a,b\in I$ such that $y$ is defined on $(a,b)$, there exists $K$ such that $|y(x)|\leq K$ for all $x\in (a,b)$, then $y$ is defined on $I$. How can I use the above to solve the problem? Why is $y$ bounded? Otherwise, how I can use the 1. and 2. to prove that $y$ is defined on $\Bbb R$? Some detail is appreciated, not because I'm lazy but because I feel like I need it.

This isn't homework. I have no idea what theorems I should be looking at to solve this. Guidance, partial and total solutions are all welcomed. Let $f$ be a locally lipschitz function in an open set $G\subseteq \Bbb R^n$. Consider the autonomous system $y'=f(y)$. Let $y(x,\xi)$ be the value at point $x$ of the maximal solution that satisfies the initial condition $y(0)=\xi$. Prove that the domain of $y(\cdot, y(s, \xi))$ is $I-s$, where $I$ is the domain of $y(\cdot ,\xi)$. Prove that for all $s, t$ such that $y(s, \xi)$ and $y(t+s, \xi)$ exist, then $y(t,y(s,\xi))$ also exists and $y(t,y(s,\xi))=y(t+s, \xi)$. If $y$ is a maximal solution and there exists $T>0$ such that $y(0)=y(T)$ and $f(y(0))\neq 0$, then $y$ is a periodic solution and not constant. If $y$ is a solution whose domain is $(a,+\infty)$, if $\eta:=\lim _{x\to +\infty}y(x)$ and $\eta \in G$, then $f(\eta)=0$. EDIT I found an alternative solution for 3. Please check my proof and give feedback in comments: let $u$ be the restriction of $y$ to $[0,T]$, now let $\overline u$ be the periodic extension of $u$ to $\mathbb R$. It is easy to see that $\overline u$ is a solution to the given differential equation. But since $f$ is locally lipschitz, $\overline u$ must coincide with $y$ wherever they are both defined. Since $y$ is a maximal solution, it must be $\overline u$, so $y$ is defined on $\mathbb R$.

I am trying to write a shell script that deletes a persistent but unnecessary folder in my home directory upon execution. So, I ask you fellow Ubuntu users, what is the terminal command to delete a file/folder?

How do I delete the following directory? I typed: rmdir lampp This error comes up: rmdir: failed to remove `lampp': Directory not empty Is there a command to delete all the files in the directory and delete the directory folder?

In the first book of the Artemis Fowl series, Fowl Manor has been placed in a magically induced time-stop, which theoretically traps anyone inside it at the time that it was started. Communication with the outside world is completely cut off, and a side effect on living creatures is that they can't fall asleep if they were awake when the stop started, and vice versa. A major plot point towards the end of the book is that someone can force themselves out of the time-stop by taking sleeping pills. The change in consciousness essentially spits them out of the past (where time is stopped) and into the present. To people in the time-stop, those who have left seem to have vanished, as evidenced by Artemis's mother disappearing from security footage earlier in the book. In chapter 9, there a bit of a political power struggle between two fairy officers, which ends with one of them (Acting Commander Cudgeon) being knocked out by a tranq dart. However, he doesn't appear to exit the time stop. Is there any explanation given (either in the books or other supplementary materials) as to why this is the case?

In Book 1, Artemis et al escaped from the time stop by drugging themselves to sleep. In the same time stop, Julius Root "accidentally" plugged Briar Cudgeon with a tranquilizer dart. Cudgeon fell asleep, but did not disappear from the time stop. Why not?

I need to solve this using Lagrange's theorem and simple corollaries. Thanks.

I need to know if every group whose order is a power of a prime $p$ contains an element of order $p$? Should I proceed by picking an element $g$ of the group and proving that there is an element in $\langle g \rangle$ that has order $p$?

To prove $\sum_{d|n}\phi(d)=n$. What is the easiest proof for this to tell my first year undergraduate junior. I do not want any Mobius inversion etc only elementry proof. Tthanks!

If $k$ is a positive natural number then $\phi(k)$ denotes the number of natural numbers less than $k$ which are prime to $k$. I have seen proofs that $n = \sum_{k|n} \phi(k)$ which basically partitions $\mathbb{Z}/n\mathbb{Z}$ into subsets of elements of order $k$ (of which there are $\phi(k)$-many) as $k$ ranges over divisors of $n$. But everything we know about $\mathbb{Z}/n\mathbb{Z}$ comes from elementary number theory (division with remainder, bezout relations, divisibility), so the above relation should be provable without invoking the structure of the group $\mathbb{Z}/n\mathbb{Z}$. Does anyone have a nice, clear, proof which avoids $\mathbb{Z}/n\mathbb{Z}$?

So I have 2 partitions, one of which is /boot and the other is everything else in an LVM logical volume. Problem is I'm getting warnings about how much space is on /boot. Warnings are increasingly frequent so I figured I better resize. I made a boot disk, specifically gparted live with tuxboot. It works fine but I can't get the volume to resize. I can see the logical volume and I can deactivate it but this does not seem to allow any resizing. I note the logical partition is yellow and the boot partition is only partly yellow. Does this mean it's full? ...because it's not. Clues?? Thanks

I want to shrink my second (LVM) partition, in order to create a new partition in the newly freed space. I am using the Live CD to do so, because I know I can't resize/move this partition while it is in use. When I opened GParted in the Live CD, I realized that I could not resize the partition, because when I right-click it, the option "resize/move" is disabled. I tried to unmount it, to "lazy" unmount it (umount -l /dev/sda2) but it didn't work. A screenshot from GParted:

I am in the process of learning Rust and am still having some issues with borrowing and ownership. I find myself trying to borrow mutable references that are already borrowed as immutable references etc... I noticed that when I try to iterate over the primes without owning them, I encounter issues trying to modify the composites hash map. I was able to get around this by calling to_owned on the vector. Is this the right way to handle this? This uses the . cargo -V cargo 1.35.0-nightly (0e35bd8af 2019-03-13) #![feature(generators, generator_trait)] use std::collections::HashMap; use std::ops::{Generator, GeneratorState}; let mut sieve = || { let mut x: u32 = 2; let mut composites: HashMap<u32, Vec<u32>> = HashMap::new(); loop { match composites.get(&x) { Some(primes) => { for _prime in primes.to_owned() { composites .entry(x + _prime) .and_modify(|v| v.push(_prime)) .or_insert(vec![_prime]); composites.remove(&x); } } None => { yield x; composites.insert(x * x, vec![x]); } } x = x + 1; } };

I am in the process of learning Rust and am still having some issues with borrowing and ownership. I find myself trying to borrow mutable references that are already borrowed as immutable references etc... I noticed that when I try to iterate over the primes without owning them, I encounter issues trying to modify the composites hash map. I was able to get around this by calling to_owned on the vector. Is this the right way to handle this? I also see that when I build the code, I get warnings about unused code for warning: struct is never constructed: 'Sieve' and warning: method is never used: 'new', am I constructing them incorrectly? use std::collections::HashMap; struct Sieve { composites: HashMap<u64, Vec<u64>>, x: u64, } impl Sieve { fn new() -> Sieve { Sieve { composites: HashMap::new(), x: 2, } } } impl Iterator for Sieve { type Item = u64; fn next(&mut self) -> Option<u64> { let x = self.x; self.x = self.x + 1; match self.composites.get(&x) { Some(numbers) => { for _num in numbers.to_owned() { self.composites .entry(x + _num) .and_modify(|v| v.push(_num)) .or_insert(vec![_num]); } self.composites.remove(&x); self.next() } None => { self.composites.insert(x * x, vec![x]); Some(x) } } } } fn main() { let mut sieve = Sieve::new(); println!("{:?}", sieve.next()); // 2 println!("{:?}", sieve.next()); // 3 println!("{:?}", sieve.next()); // 5 println!("{:?}", sieve.next()); // 7 } . I , this made it difficult to get feedback on. I have refactored the code to use iterators

I am trying to access java swing components from a different class. For example, I need to change the text on a button once a specific operation has been completed. I am trying to use "getters" and "setters" to do the operation(at the bottom of the section of code.) Right now I only want to "set" the text. I have another class that calls the "set" method and tries to set the text of the chosen button. This is the main class. The line of code that is "gui.setProcessItemBtn().setText("Some Text");" Throws: Exception in thread "main" java.lang.NullPointerException I believe this means that there isnt anything to set the text to. Am i missing something to link my setter methods to the actual gui components? Main class package book; import book.UserInterface; /** * * @author KJ4CC */ public class Book { /** * @param args the command line arguments */ public static void main(String[] args) { UserInterface gui = new UserInterface(); gui.startUI(); gui.setProcessItemBtn().setText("Some Text"); } } User Interface class public class UserInterface extends JFrame { private JButton processItem; private JButton confirmItem; private JButton viewOrder; private JButton finishOrder; private JButton newOrder; private JButton exit; public void startUI(){ UserInterface gui = new UserInterface(); gui.bookingUI(); } public static void bookingUI(){ //sets windows, and pane in the UI JFrame frame = new JFrame("Ye old Book stoppe"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JPanel toppane = new JPanel(new GridBagLayout()); JPanel bottomPane = new JPanel(new GridBagLayout()); GridBagConstraints c = new GridBagConstraints(); frame.setSize(800, 300); frame.setVisible(true); //adds labels to the window //----------------------------------------------------------BUTTOM PANE------------------------- //setting up buttons to be placed onto the bottompanel JButton processItem = new JButton("Process Item"); JButton confirmItem = new JButton("Confirm Item"); JButton viewOrder = new JButton("View Order"); JButton finishOrder = new JButton("Finish Order "); JButton newOrder = new JButton("New Order"); JButton exit = new JButton("Exit"); //adding the buttons to the pane.--------------------------------------------------------------- GridBagConstraints b = new GridBagConstraints(); b.insets = new Insets(5,5,5,5); b.ipadx = 10; b.ipady = 10; b.gridx = 1; b.gridy = 0; bottomPane.add(processItem, b); b.gridx = 2; b.gridy = 0; bottomPane.add(confirmItem,b); confirmItem.setEnabled(false); b.gridx = 3; b.gridy = 0; bottomPane.add(viewOrder, b); viewOrder.setEnabled(false); b.gridx = 4; b.gridy = 0; bottomPane.add(finishOrder,b); finishOrder.setEnabled(false); b.gridx = 5; b.gridy = 0; bottomPane.add(newOrder,b); b.gridx = 6; b.gridy = 0; bottomPane.add(exit, b); bottomPane.setBackground(Color.BLUE); frame.add(bottomPane,BorderLayout.SOUTH); frame.setSize(810, 310); } //Creating getters and setters to change the text for the buttons and labels. public JButton setProcessItemBtn(){ return processItem; } public JButton setConfirmItemBtn(){ return confirmItem; } public JButton setViewOrderbtn(){ return viewOrder; } public JButton setFinishOrderBtn(){ return finishOrder; } public JButton setNewOrderBtn(){ return newOrder; } public JButton setsetExitBtn(){ return exit; }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them? What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?

The verb 'seem' is a specimen linking verb, as in: (1) He seems a nice guy. But it can have a clause as its complement, as in: (2) He seems to be a nice guy. [to-infinitive clause] (3) It seems that he is a nice guy. [that-clause] In (2) or (3) or both, is the verb 'seem' still a linking verb or something else? Answers to , don't specifically say whether the verb 'seem' as in (2) or (3) can be classified as a linking verb or not. If you or anyone can locate anything close to a possible answer to my question in the link, please let me know.

Is there any difference between these expressions? It seems like they have not completed the task yet. It seems that they have not completed the task yet. It seems they haven't completed the task yet.

I can not understand key difference between them, because all on the web uses mathematical notations...Can anyone explain in easy way?...please.Thanks in advance.

Rings, groups, and fields all feel similar. What are the differences between them, both in definition and in how they are used?

How does this work? i have dual Nigerian-British citizenship and i want to travel to the US from Nigeria. if I travel to the US with a british passport ( with ESTA of course) i will need to give the airline details of my UK Passport. When departing, the airline will need my pp details on checkin and i provide my Nigerian pp details as it wont accept my british pp (saying i will need a visa). how will the US know that the same person who entered with british pp is the same one departing with a Nigerian one?

I am a citizen of two different countries, and have two passports. How should I use my passports when traveling?

Ok I don't know if I'll explain this properly. I have no idea what I've selected to make this happen but it's messing with my head. In my current project I cannot move a mesh in Object mode, I need to be in edit mode. If I duplicate in object mode using shift D it seems to add a new mesh, but I can only move the visible Move icon. I have no idea what this is option/function is for. See image below: If a create a new project with a mesh, I can move the mesh by pressing G. Or when I press shift D it immediately moves the duplicated mesh and can be moved as below: What on earth have I done? I've searched through all the menus I can think of I don't know what option I've selected to make this happen, but I don't like it. Appreciate any help with this.

I can only move the origin point of the mesh that I selected in object mode, but not the whole mesh Did I set anything up by accident?

Determine the largest integer $n$ which has at most three digits and equals the remainder when $n^2$ is divided by $1000$. I've determined that the last digit can only be 1, 5, or 6, but if I try to continue, I meet some problems with $n^2$.

Find the smallest integer $n$ greater than $1$ such that the last $3$ digits of $n^2$ are the same as the last $3$ digits of $n$. So far I've got $n^2 = 1000k + n$ which means $n^2 ≡ n \mod 1000$. I don't know how to proceed since 1000 seems to be a bit high.

Suppose I buy a big box of assorted sweets. There are 10 distinct types of sweets, all evenly distributed in their assortment. I am separating them out into party bags for a party. I make up 100 party bags, each containing four distinct sweets. As such there are 400 sweets in total, with 40 of each variety distributed amongst the bags. The question is, if I look inside $n$ bags (without replacement), what is the probability that I will have seen every variety of sweet? I appreciate that if I knew the exact tally of sweet varieties I wanted to find I could use a multivariate hypergeometric distribution. This is a version of the coupon collecting problem but without replacement. It may be that this problem isn't easily analytically solvable? Am I doomed to be unable to do this for such a large dimension of variables? Any advice or input would be greatly appreciated. Perhaps calculating a Chao index is required?

I was looking at various extensions of the classical Coupon Collector problem, but couldn't find any answers or hints for the following modification: Assume there are $n$ distinct coupons and you get them in batches of a different (random) size. That is, assume that every time you get a black box with coupons in it, whose number can be from $0$ to $n$ and coupons within a black box are distinct. The probability of having a specific coupon in a box is $p$ (that is, it's the same for all). What is the expected number of black-boxes one needs to open to collect all coupons?

I've been reading up on the of Quantum Mechanics, and there is one thing (among many) that I really don't understand. How many worlds are 'created' by an 'observation' or 'event'? For example, in the traditional Schrödinger's Cat experiment a cat is put into a box with a poison flask that has a chance of breaking, with the cat dying if it does. But how many worlds are created by this? If the probabilities are even I could understand two worlds being created. But what if the flask has a 70% chance of breaking? Are ten worlds created, in seven of which the cat is dead? Or are an infinite number created, but in 70% of which the cat is dead? Or are just two created, but you somehow have a 70% chance of ending up in the world with the dead cat? Or is it something entirely different?

When I read descriptions of the many-worlds interpretation of quantum mechanics, they say things like "every possible outcome of every event defines or exists in its own history or world", but is this really accurate? This seems to imply that the universe only split at particular moments when "events" happen. This also seems to imply that the universe only splits into a finite number of "every possible outcome". I imagine things differently. Rather than splitting into a finite number of universes at discrete times, I imagine that at every moment the universe splits into an uncountably infinite number of universes, perhaps as described by the Schrödinger equation. Which interpretation is right? (Or otherwise, what is the right interpretation?) If I'm right, how does one describe such a vast space mathematically? Is this a Hilbert space? If so, is it a particular subset of Hilbert space?

I would like to install the gpointing-device-settings package which I found on the Launchpad website I tried: apt-get install gpointing-device-settings but I get the following reply: E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root? I also tried add-apt-repository ppa:gpointing-device-settings and got Error: must run as priviledged user Can anyone point me in the right direction please as I seem to have got my brain into a loop...

I get this error whenever I try to install programs using the terminal: home@ubuntu:~$ apt-get install myunity E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied) E: Unable to lock the administration directory (/var/lib/dpkg/), are you root? Also I'm unable to install updates using the terminal.

I want know the advantages of using digital signatures over HMAC for message by message authentication. I know that HMACs are inexpensive to implement compared to DS, but DS provides a very strong security also uses more processing power. Are these two the main differences?

I know the definitions of both but can't specifically tell how they are different and if one is better than the other. Please help.

What kind of checks and balances are in place for over-zealous, puritan moderators who seem to have nothing better to do with their time than make it very difficult for people with genuine questions to get answers? Case in point- I was working on an answer to on GIS Stack Exchange, which I considered to be on-topic. The OP was asking a programming question related to prominent GIS software and features. Next thing I know, the question is put on hold as off-topic. Per the page: Keep the site reasonably on topic by closing, migrating, or removing blatantly off-topic questions. With as little reputation as I have, is there nothing I can do to help users like this escape the oppressiveness and get answers to their questions?

One or more of the following things happened to me on a Stack Exchange site: My post(s) were wrongly deleted or locked by a moderator A moderator posted a wrong comment on one of my posts I was suspended, but did not do anything wrong I asked a meta question, but the question was closed and/or deleted A moderator discredited me in public ... I think a moderator has abused their power, but I feel powerless against them. What recourse do I have now? What can I do when I feel that a moderator has abused their power, and has been repeatedly unfair in their dealings with me?

How to prove the following?: Let $m,n\in \mathbb{N}$ ; $ \;m^{2}\mid n^{2}\Longrightarrow \;\;m\mid n$ Just a hint please. I tried two ways but did not work.

Let $a$ and $b$ be positive integers. Prove that: If $a^2$ divides $b^2$, then $a$ divides $b$. Context: the lecturer wrote this up in my notes without proving it, but I can't seem to figure out why it's true. Would appreciate a solution.

So I was solving maths problems in Hackerrank and I found this problem : . So this problem was little bit of maths so I was facing difficulties to solve this. The description of this problem: Adam is standing at point (a,b) in an infinite 2D grid. He wants to know if he can reach point (x,y) or not. The only operation he can do is to move to point(a+b,b),(a,a+b),(a-b,b),(a,b-a) from some point . It is given that he can move to any point on this 2D grid, i.e., the points having positive X or negative (or Y) co-ordinates. Tell Adam whether he can reach or not. So I see the answer and the answer was: return gcd(a,b)==gcd(x,y) Which basically means if the gcd of the two initial points and the target points is the same then there exists a solution other there isn't. But I don't understand even a little bit of it why this is the answer.Can you explain me briefly? I understand the mathematical logics but I also wanna understand why it is mathematically correct.

I understand GCD mathematically but i can't figure out where to apply it. For eg I saw this problem today: Adam is standing at point $(a,b)\in\mathbb Z^2$ in an infinite 2D grid. He wants to know if he can reach point $(x,y)$ or not. The only operations he can do is to move to the points $(a+b,b), (a,a+b), (a-b,b)\text{ or }(a,a-b)$ from some point $(a,b)$. It is given that he can move to any point on this 2D grid, i.e. the pointscan have positive or negative $x$(or $y$) coordinates. Tell Adam whether he can reach $(x,y)$ or not. The solution to this problem is simple: If $\gcd(x,y) = \gcd (a,b)$ then adam can reach $(x,y)$ from $(a,b)$, otherwise not. While this solution is indeed working I am not able to figure out how to come up with it. What is the significance of $\gcd$ in this question?

How can I show that a sequence of regular polygons with n sides becomes more and more like a circle as n→∞? In which fields this concept is applied?

What are the various fields in which circle is treated as infinite sided regular polygon? What I actually mean is , "can u suggest me some applications where circle is treated as infinite sided polygon." for example parallax method .

Can Ubuntu be installed on an old laptop as an operating system? Is Ubuntu an operating system or does it operate as a browser only?

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and such as: with a lighter desktop than the usual Gnome and Unity with the even lighter LXDE desktop Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?

The asserts that our system of Arabic numerals is a geometric design where the number of corners corresponds to the number represented: My question is: Is our Arabic number system based on a geometric design counting corners?

Why are the ten digits in base 10 noted $0, 1, 2 ,3 ,4 ,5 ,6 ,7 ,8 ,9$ ? I heard it has to do with angles, but since I can't see how $9$ has $9$ angles, this may not be the historical reason ?

I want to prove $\alpha \rightarrow \beta, (\alpha \rightarrow \lambda) \rightarrow \beta $ proves $\beta$ in HPC I use MP and the axioms listed here: I guess that the end of the proof should look something like this: $(\alpha\rightarrow(\beta\rightarrow\lambda)) \rightarrow ((\alpha \rightarrow \beta) \rightarrow (\alpha \rightarrow\lambda))$ $(\alpha \rightarrow \beta) \rightarrow (\alpha \rightarrow\lambda)$ $\alpha \rightarrow \lambda$ $\beta$ but I can't find out how I can get to $(\alpha\rightarrow(\beta\rightarrow\lambda))$ given my premises would be happy for some help

I'd really like your help proving: $(A\rightarrow B),(A\rightarrow C)\rightarrow B, \mapsto_{HPC} B $ Where $HPC$ is the Hilbert's system proof which contains the following relevant axioms: $A\rightarrow(B \rightarrow A)$ $(A\rightarrow(B\rightarrow C)) \to ((A\rightarrow B)\rightarrow(A\rightarrow C))$ $(A\rightarrow B)\rightarrow ((A\rightarrow\bar{B})\rightarrow \bar{A})$ $\bar{\bar{A}} \rightarrow A$ In addition tried to use these following lemmas: $\bar{A} \rightarrow (A \rightarrow C) $ and $(A\rightarrow B)\rightarrow (\bar{B} \rightarrow \bar{A})$. Any suggestions?

I have a Windows 10 laptop, do I need to install Ubuntu before I can install Ubuntu Server for managing SSH and web hosting?

What's the difference between the server version of Ubuntu and the desktop version?

I am designing a logo for a friend. I have the font and colors done. All I need is an icon for it. I found a vector on shutterstock that would be perfect. I took the vector and used it as a base and re-designed it so it's completely different from the original. Should i be worried about copyright and licencing.

My company bought and wants to trademark it by adding some words with different colors. Do you know anything about if this is legal since we purchase the vector art?

Hi My son will be joining Bsc in computer science from TU Delft Netherlands after completing 12 years of school education from India. Will he be eligible for MS after his graduation from. US universities?

I am an Indian citizen and I'm planning to go for my bachelors to Germany. Since schooling in Germany is 13 years in length, I'll study 1 year in India before going there. I wanted to ask that after completing my Bachelor's in Germany, will I be eligible to apply for Masters in USA straightaway right after my BS (I plan to pursue a BS in Computer Science). I had this doubt in my mind as BS in Germany would be 3 years compared to that in USA which is 4 years.

I recently noticed that I have entries from an unknown IP address in my SSH logs. I performed a grep to extract all entires that didn't contain my own IP address. I was presented with this: Jul 24 22:06:54 server1 sshd[8261]: Accepted publickey for root from xxx.xxx.xx.xxx port 39721 ssh2 Jul 25 04:06:50 server1 sshd[8233]: Accepted publickey for root from xxx.xxx.xx.xxx port 40800 ssh2 Jul 25 04:08:30 server1 sshd[8233]: Received disconnect from xxx.xxx.xx.xxx: 11: disconnected by user I have a few questions: Are the first two lines successfull or attempted log ins? Is the third line a disconnect resulting from a successfull or attempted log in? Is the four digit number in square brackets after sshd the PID? I'm running CentOS 5 on a dedicated server. I am using OpenSSH.

This is a about Server Security - Responding to Breach Events (Hacking) See Also: Canonical Version I suspect that one or more of my servers is compromised by a hacker, virus, or other mechanism: What are my first steps? When I arrive on site should I disconnect the server, preserve "evidence", are there other initial considerations? How do I go about getting services back online? How do I prevent the same thing from happening immediately again? Are there best practices or methodologies for learning from this incident? If I wanted to put a Incident Response Plan together, where would I start? Should this be part of my Disaster Recovery or Business Continuity Planning? Original Version 2011.01.02 - I'm on my way into work at 9.30 p.m. on a Sunday because our server has been compromised somehow and was resulting in a attack on our provider. The servers access to the Internet has been shut down which means over 5-600 of our clients sites are now down. Now this could be an FTP hack, or some weakness in code somewhere. I'm not sure till I get there. How can I track this down quickly? We're in for a whole lot of litigation if I don't get the server back up ASAP. Any help is appreciated. We are running Open SUSE 11.0. 2011.01.03 - Thanks to everyone for your help. Luckily I WASN'T the only person responsible for this server, just the nearest. We managed to resolve this problem, although it may not apply to many others in a different situation. I'll detail what we did. We unplugged the server from the net. It was performing (attempting to perform) a Denial Of Service attack on another server in Indonesia, and the guilty party was also based there. We firstly tried to identify where on the server this was coming from, considering we have over 500 sites on the server, we expected to be moonlighting for some time. However, with SSH access still, we ran a command to find all files edited or created in the time the attacks started. Luckily, the offending file was created over the winter holidays which meant that not many other files were created on the server at that time. We were then able to identify the offending file which was inside the uploaded images folder within a website. After a short cigarette break we concluded that, due to the files location, it must have been uploaded via a file upload facility that was inadequetly secured. After some googling, we found that there was a security vulnerability that allowed files to be uploaded, within the ZenCart admin panel, for a picture for a record company. (The section that it never really even used), posting this form just uploaded any file, it did not check the extension of the file, and didn't even check to see if the user was logged in. This meant that any files could be uploaded, including a PHP file for the attack. We secured the vulnerability with ZenCart on the infected site, and removed the offending files. The job was done, and I was home for 2 a.m. The Moral - Always apply security patches for ZenCart, or any other CMS system for that matter. As when security updates are released, the whole world is made aware of the vulnerability. - Always do backups, and backup your backups. - Employ or arrange for someone that will be there in times like these. To prevent anyone from relying on a panicy post on Server Fault.

Is it possible to have a panel with stl files (or icons representing them) that can be dragged and dropped into the Viewport? I've read through a number of forum posts claiming that it was in the works at some point, but I can seem to find anything conclusive. Is there an add-on that allows that functionality? Thanks!

Is there away to click and drag an STL file from a folder or my desktop to Blender? or do I have to use the old fashion way file-import?

I am trying to write a math paper, and I need to write the following symbol: $\overline{\underline{X}}$ Is there any package that already contains it?

This question led to a new package: (using a variation of egreg's code, and stating this in the manual; the package isn't really new now, sorry for the delayed announcement) I have read about "How to get Roman numerals" but asked myself how to get Roman numerals formatted as in i.e. with fitted over- and underline (without manually using boxes and such)? I'm curious for your answer(s)!

Say that Amy tosses a coin 6 times, and Bob tosses a coin 5 times. What's the probability that Amy gets more heads than Bob does?

Say Bob tosses his $n+1$ fair coins and Alice tosses her $n$ fair coins. Lets assume independent coin tosses. Now after all the $2n+1$ coin tosses one wants to know the probability that Bob has gotten more heads than Alice. The way I thought of it is this : if Bob gets $0$ heads then there is no way he can get more heads than Alice. Otherwise the number of heads Bob can get which allows him to win is anything in the set $\{1,2,\dots,n+1\}$. And if Bob gets $x$ heads then the number of heads that Alice can get is anything in the set $\{0,1,2,..,x-1\}$. So\begin{align}P(\text{Bob gets more heads than Alice})&= \sum_{x=1}^{n+1} \sum_{y=0}^{x-1} P( \text{Bob gets x heads }\cap \text{Alice gets y heads }) \\[0.2cm]&= \sum_{x=1}^{n+1} \sum_{y=0}^{x-1} \left(C^{n+1}_x \frac{1}{2}^{x} \frac{1}{2}^{n+1-x}\right)\left( C^n_y \frac{1}{2}^y \frac {1}{2}^{n-y}\right)\\[0.2cm]& = \sum_{x=1}^{n+1} \sum_{y=0}^{x-1} \frac{C^{n+1}_x C^n_y}{2^{2n+1}}\end{align} How does one simplify this? Apparently the answer is $\frac{1}{2}$ by an argument which looks like this, Since Bob tosses one more coin that Alice, it is impossible that they toss both the same number of heads and the same number of tails. So Bob tosses either more heads than Alice or more tails than Alice (but not both). Since the coins are fair, these events are equally likely by symmetry, so both events have probability 1/2.

I created a python qgis action that open the dialog form so the user can add a new feature. maintenance_lyr = QgsMapLayerRegistry.instance().mapLayer('od_maintenance_event20180212171049766') maintenance_lyr.startEditing() qgis.utils.iface.setActiveLayer(maintenance_lyr) qgis.utils.iface.actionAddFeature().trigger() My question: How can I get the id of the newly created feature?

I'm trying to make an edit form in QGIS (Python code) ,and i want after feature drawing to get the id, and the feature to be selected. Do you have any ideas to do that? Tried so far: self.iface.activeLayer().featureAdded.connect(self.myfonction) def myfonction(self): for feat in self.iface.activeLayer().getFeatures(): self.iface.activeLayer().setSelectedFeatures([feat.id()])

Is it still the case that Purgeable part is not under our control (to be deleted)? There are several posts (e.g., ) on this, but no solution as it seems.

I cleared space on my disk by deleting files and emptying trash. But, I am unable to make use of the space that I freed up. That is, as you can see the disk reports 142 GB as Available with 83 GB of that as purgeable. So I should have plenty of space to to copy over a 70 GB file onto the disk. Yet when I try I get an error stating "Not enough disk space to copy", like the following image shows: How do I clear out the purgeable space to make it truly available for use? I've tried rebooting in the hopes that a restart clears out the purgeable area, but had no change trying that.

I'm installing Ubuntu 16.04 with manual partitioning, and need to choose a separate partition for /var/log. However, in the installer, there does not seem to be an option for doing this. The drop-down menu only has /, /boot, /home, /tmp, /usr, /var, /srv, /opt, and /usr/local. What is the easiest way to put /var/log on a separate partition?

I'd like to see the full How-To on how to use manual partitioning during Ubuntu installation. The existing guides (at least those I found here) cover only automatic part and leave untouched the manual part (or extremely short and contain no pictures). I'd like to cover such situations: If your disk contains other systems:

Error mounting /dev/sda2 at /media/rajeev/A480692B80690560: Command-line `mount -t "ntfs" -o "uhelper=udisks2,nodev,nosuid,uid=1000,gid=1000,dmask=0077,fmask=0177" "/dev/sda2" "/media/rajeev/A480692B80690560"' exited with non-zero exit status 14: Windows is hibernated, refused to mount. Failed to mount '/dev/sda2': Operation not permitted The NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting), or mount the volume read-only with the 'ro' mount option.

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount. When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens. Here's my partition table, if any more data is needed please let me know. Device Boot Start End Blocks Id System /dev/sda1 2048 20000767 9999360 83 Linux /dev/sda2 20002814 478001151 228999169 5 Extended /dev/sda3 * 478001152 622532607 72265728 7 HPFS/NTFS/exFAT /dev/sda4 622532608 625141759 1304576 82 Linux swap / Solaris /dev/sda5 20002816 478001151 228999168 83 Linux

This is my code. I want to know what is happening here. Can anybody describe the code? char *string; string = "Le Casa de Papel"; *(str+1) = 'a'; return 0;

The following code receives seg fault on line 2: char *str = "string"; str[0] = 'z'; // could be also written as *str = 'z' printf("%s\n", str); While this works perfectly well: char str[] = "string"; str[0] = 'z'; printf("%s\n", str); Tested with MSVC and GCC.

The Mac OS X 10.10 (Yosemite) installer fails to extract any files onto my drive: OS X could not be installed on your computer An error occurred while extracting files from the package "Essentials.pkg". Quit the installer to restart your computer and try again. However, I have reinstalled Mac OS X 10.9.5 (Mavericks) just fine, which leads me to believe there’s something wonky going on with the installer. Judging by the comments on , it seems like this error might be occurring with people who have installed SSDs in their old MacBooks. I have a mid-2010 MacBook with a 512GB SSD in the main hard drive slot and a secondary 250GB HDD in the DVD drive bay. I also have installed 16GB of RAM in this laptop. So far all of the new hardware has worked fine for the past 6 months so I doubt my issues are due to faulty hardware. I am trying to perform the install on a freshly formatted partition. Here is the . Here’s from when I was trying to upgrade the OS instead of using a freshly formatted partition.

I'm getting this error: OS X could not be installed on your computer An error occurred while extracting files from the package "Essentials.pkg". Quit the installer to restart your computer and try again. Every time I restart, it installs until "19 minutes" are left and gives me the exact same error. I have no idea what to do because apparently no one else is having this problem.

I try to setup my .gitignore file. My local repo is a clone from my Drupal 8 distro from Acquia Cloud. (I want to theme my template locally and then, step by step I want to push it to Dev on Acquia Cloud.) So regarding handeling settings.php, whether or not to ignore settings.php and whether or not use settings.local.php: If I look in my current settings.php is see this: // On Acquia Cloud, this include file configures Drupal to use the correct // database in each site environment (Dev, Stage, or Prod). To use this // settings.php for development on your local workstation, set $db_url // (Drupal 5 or 6) or $databases (Drupal 7 or 8) as described in comments above. I am confused and don't know anymore how to setup my .gitignore file with all this information and whether or not use settings.local.php. Please can somebody advice my what I have to do exactly, so it's setup correctly from the beginning.

I want to add .gitignore file to my local repo. My local repo is a clone from my Drupal 8 distro from Acquia Cloud. What are best practices for my .gitignore file for Acquia Cloud hosted sites? I followed . For example: do i have to ignore settings.php and not settings*.php? Regarding this quote from : Drupal 8 You can modify .gitignore so that it ignores settings.php (not settings*.php). Then, you can update the standard settings.php with the Drupal 8 local settings file checker: Where is settings.local.php for, mentioned in the Quote above from ? Currently my .gitignore file looks like this: # This file contains default .gitignore rules. To use it, copy it to .gitignore, # and it will cause files like your settings.php and user-uploaded files to be # excluded from Git version control. This is a common strategy to avoid # accidentally including private information in public repositories and patch # files. # # Because .gitignore can be specific to your site, this file has a different # name; updating Drupal core will not override your custom .gitignore file. # Ignore core and vendor when managing dependencies with Composer. # core # vendor # Ignore configuration files that may contain sensitive information. sites/*/settings*.php sites/*/services*.yml # Ignore paths that contain user-generated content. sites/*/files sites/*/private sites/*/files-private cache/ files/ # Ignore SimpleTest multi-site environment. sites/simpletest # If you prefer to store your .gitignore file in the sites/ folder, comment # or delete the previous settings and uncomment the following ones, instead. # Ignore configuration files that may contain sensitive information. # */settings*.php # Ignore paths that contain user-generated content. # */files # */private # Ignore SimpleTest multi-site environment. # simpletest # Ignore default text files /CHANGELOG.txt /COPYRIGHT.txt /INSTALL*.txt /LICENSE.txt /MAINTAINERS.txt /UPGRADE.txt /README.txt sites/all/README.txt sites/all/modules/README.txt sites/all/themes/README.txt # ------------------------------------------------------------------------------ # SublimeText files # ------------------------------------------------------------------------------ # Workspace settings. *.sublime-workspace # Project settings. *.sublime-project # ------------------------------------------------------------------------------ # OSX # ------------------------------------------------------------------------------ # Common OSX files. .AppleDouble .DS_Store .LSOverride # Thumbnails. ._* # Files that might appear in the root of a volume. .DocumentRevisions-V100 .fseventsd .Spotlight-V100 .TemporaryItems .Trashes .VolumeIcon.icns # Directories potentially created on remote AFP share. .apdisk .AppleDB .AppleDesktop Network Trash Folder Temporary Items # ------------------------------------------------------------------------------ # Windows # ------------------------------------------------------------------------------ # Windows image file caches. ehthumbs.db Thumbs.db # Folder config file. Desktop.ini # Recycle Bin used on file shares. $RECYCLE.BIN/ # Windows Installer files. *.cab *.msi *.msm *.msp # Windows shortcuts. *.lnk # ------------------------------------------------------------------------------ # Linux # ------------------------------------------------------------------------------ # Tilde files. *~ # KDE directory preferences. .directory # Linux trash folder which might appear on any partition or disk. .Trash-* What do i have to change to make it perfect?

I was in the middle of a dialogue when i was arrested in skyrim and now I have no control of my character. I can still move the camera a bit and open the menus but I can't walk or quick travel. Also using the console command "enableplayercontrols" has no effect and does not do anything.

I can look around, but I can't jump, I can't attack and I can't switch from third-to first person. I brawled with Vilkas at Jorrvaskr to prove my worth for the Companions, and when I left dialogue, I couldn't move. I can't open any menus, except for settings, and quest. I tried quicksaving and reloading, and I tried restarting, but neither worked. Can I get some help? I'm playing on a laptop PC.

I moved to the US when I was 5 and moved back to my home country at the age of 13. Its been 13 years since then. I want to travel to the US for a short holiday and was wondering if I would get denied the ESTA for the Visa Waiver. Specially since I have to answer "yes" to the "8) Have you ever stayed in the United States longer than the admission period granted to you by the U.S. government?" question. I know that overstaying as a minor doesn't really count for ban purposes, but I'm not sure what will happen when I apply. Any insights? Thanks :)

I can't seem to find a story related to mine so here it is. I am 25 and a German citizen. In 1998 when I was 7 years old my family moved to the states and we stayed until early 2002 and left voluntarily. Basically we overstayed. I am aware that my parents had the ten year ban and since I was a minor at the time of our overstay I did not receive such ban. Ever since 2002 I have not attempted to go back to the USA for any reason. However now that I am older I would like to go back for vacation and stay for a short period of time (one month) during my christmas break. I've lived in Germany since leaving, have a great job, enough money in the bank account. My whole life is here and I have no intention on moving anywhere else. After reading a bunch of stories online I have decided to apply for a B2 visa to be on the safe side but I was curious about the ESTA approval. For the last question. 8) Have you ever stayed in the United States longer than the admission period granted to you by the U.S. government? I should put yes but is it a no if I stayed when I was a minor? And what are my chances on getting the B2 Visa?

I am trying to display some banner from a remote location using hrefs and img in JavaScript. On client side: <script src="data/JScript.js?id=123" type="text/javascript"></script> I want some solution so that I can make 123 dynamic in below JS file. As of now it is hard coded. I just want that i will give client the above JS link and it will generate a dynamic link to a website with a querystring paramenter like (www.abc.com/123) JS file (JScript.js): document.write('<div style="text-align:center" class="img-responsive" ><a href="www.test.com/123" > <img style="width:200px;height:200px;" src="http://pixel.nymag.com/imgs/daily/intelligencer/2015/07/18/20-donald-trump.w529.h352.2x.jpg" alt="" > </img> </a> </div>');

How can I reference the script element that loaded the javascript that is currently running? Here's the situation. I have a "master" script being loaded high in the page, first thing under the HEAD tag. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <script type="text/javascript" src="scripts.js"></script> There is a script in "scripts.js" which needs to be able to do on-demand loading of other scripts. The normal method doesn't quite work for me because I need to add new scripts without referencing the HEAD tag, because the HEAD element hasn't finished rendering: document.getElementsByTagName('head')[0].appendChild(v); What I want to do is reference the script element that loaded the current script so that I can then append my new dynamically loaded script tags into the DOM after it. <script type="text/javascript" src="scripts.js"></script> loaded by scripts.js--><script type="text/javascript" src="new_script1.js"></script> loaded by scripts.js --><script type="text/javascript" src="new_script2.js"></script>

Suppose I have one file like: apple | red | 2 apple | green | 3 orange | yellow | 3 apple | yellow | 1 Now I need following output as (irrespective of color value should get third number summed): apple | red | 6 orange | yellow | 3 I tried something like below: tail -n 4 $firstfile| while IFS=, read -r f2col1 f2col2 do match1=$(echo $f2col2) fruit1=$(echo $f2col1) if [ "${fruit1}" == "${fruit1}" ]; then match3=`expr ${match3} + ${match1}` which doesn't seem to be right after second addition. Could somebody give me better idea?

I have below inputs with huge number of rows 11|ABCD|19900101123123445455|555|AAA|50505050|0000009030 11|ABCD|19900101123123445455|555|AAA|50505050|0000000199 13|ABCD|201803010YYY66666666|600|ETC|20180300|0000084099 11|ABCD|19900101123123445455|555|AAA|50505050|0008995001 And I need to get below output 11|ABCD|19900101123123445455|555|AAA|50505050|9004230 13|ABCD|201803010YYY66666666|600|ETC|20180300|84099 I have been trying with below awk but having too limited knowledge with arrays. cat test|awk -F"|" '{ a[$1]++;b[$2]++;c[$3]++;d[$4]++;e[$5]++;f[$6]+=$6 }; END { for (i in a); print i, f[i]}' I need to sum last column of column number 6 and print all first 5 columns, which are separated by pipe and last 6th column as sum of 6th column.

Here's the code I'm working with currently: var request = require('request'); var options = { 'method': 'GET', 'url': `https://accounts.rec.net/account?username=actuallylegacy`, 'headers': { } }; request(options, function (error, response) { if (error) throw new Error(error); if (!response.body) { console.log("No user found by that name!") return } else { console.log(response.body); } This code outputs this: {"accountId":5225334,"username":"ActuallyLegacy","displayName":"Le_acy","profileImage":"52a12fa7a7f5436491a6205fddf00f37.jpg","bannerImage":"9939bd49de624ff0b236d366a95ff7af.jpg","isJunior":false,"platforms":4,"createdAt":"2020-05-13T19:05:26.6584486Z"} Which this is super messy, which I don't like. My goal is to be able to pull parts of this data and display it all in different "blocks". I'm not sure whether I'm just looking in the wrong places for help but, I haven't been able to find any sort of guide on how to extract data from a string. Any sort of help would be greatly appreciated! ^w^

Given a string of JSON data, how can I safely turn that string into a JavaScript object? Obviously I can do this unsafely with something like: var obj = eval("(" + json + ')'); but that leaves me vulnerable to the JSON string containing other code, which it seems very dangerous to simply eval.

The first time I applied for Schengen visa I was refused. And now, I'm confused whether I will appeal or re-apply. The following are the documents I submitted: Invitation letter from my cousin stating that he will take charge all my expenses Birth certificate as proof of relationship but not all were authenticated from National Statistics Office Bank Certificate with only enough money for my round trip ticket Passport with stamp from my Singapore travel last year Certificate of my employment stating my salary, position, length of service, compensation and benefits Company ID and 3 months payslip I was refused due to "Your intention to leave the territory of the member state before the expiry of the visa could not be ascertained."

Schengen refusal formulae can be difficult to understand sometimes. Sometimes an applicant receives a refusal with: Justification for the purpose and conditions of the intended stay was not reliable. often accompanied by: Your intention to leave the territory of the Member States before the expiry of the visa applied for could not be ascertained. What is meant by this refusal reason? What are they trying to say?

So, I wrote a review for an app. Both positive and negative thoughts in it, then I refreshed it and its not there. Help? Do I need a review account because all the people who review have some kind of username.

I have an app that's been out for a couple of weeks. Its not exactly selling like hot cakes yet, but I'm pretty sure I've gotten a rating or a review by now. But nothing shows when viewing either in iTunes or directly on the AppStore on the iPhone. Is there a standard delay as to when ratings/reviews show up, that Apple imposes, especially for new apps? Or do you think there is some problem with Apple's system?

I have a listing of files that have numeric characters at the end after a dot. ex : abc.log abc.log.1 xyz.log xyz.log.1 xyz.log.2 I need to list only the logs that have .log at the ending and not the ones with .log.1 or .log.2 at the ending.

If I do: $ ls -R .: 4Shared/ Cloud/ ./4Shared: UFAIZLV2R7.part3.rar ./Cloud: UFAIZLV2R7.part2.rar.part UFAIZLV2R7.part1.rar.part UFAIZLV2R7.part4.rar.part If I want to list the .rar files only, and I use grep, it will show me too the .rar.part files, what is not my wish. I am solving this using find or ls **/*.rar as told in and they work fine, but I would like to learn if it is possible to do it via grep. I have tried (thinking about EOL): ls -R | grep ".rar\n" with no results. I think that the problem lies in discover if the greping is found at the end of the line, but I am not sure. Any help out here, please?

Any time I open sub folders of the Music folder on this system containing MP3s with Explorer, they always have the music customization, but I tend to use file-naming conventions that don't make this customization necessary... I'd rather just see a general view. I'm using Windows 7 Home Premium, Compaq CQ2014 (2011). How do I avoid "music" customization in music sub folders?

I have an empty folder with regular details view. File name, file size, file type columns are shown and I am happy. Then I put some MP3 or WAV files in. Windows Explorer "kindly" changes the column types. It will show Genre, media length, Album and other metadata tags, but does not show the file size anymore. If I do not like it, I have to manually change the columns back. It is very irritating. How can I turn this automatic behavior off?

If I do not edit the .bashrc or other config files, the environment variables that I've setted are gone when I logout, or turn off the terminal. What I'm curious is, where are those 'temporary' env vars saved in? As I guess, they might be in the memory. That makes sense because they will disappear when the terminal is turned off(equals the terminal I was using is gone from the memory). Am I correct?

I know that VARIABLE=value creates an environment variable, and export VARIABLE=value makes it available to processes created by the current shell. env shows the current environment variables, but where do they live? What comprises an environment variable (or an environment, for that matter)?

I have written a piece of code that counts the number of lines in a file (I wasn't able to find a built-in method that could acheive this in the IO classes). My code below: try { while(!line.equals("null")) { line = bufferedReader.readLine(); a = a + 1; System.out.println(a + " " + line); } } catch (NullPointerException N) {} The problem I'm running into is that the count still increases while the variable 'line' evaluates to "null". I understand why this is the case; the while statement won't check the condition until after the entire code block has been run, in which case 'a' will have increased once again. Solutions I have considered: 1) Set 'a = -1', whereas I currently have 'a = 0' before this block of code 2) Use if statement to break the loop before the count variable is reached. This is how I would modify the code block: try { while(!line.equals("null")) { line = bufferedReader.readLine(); if (line.equals("null")) {break;} a = a + 1; System.out.println(a + " " + line); } } catch (NullPointerException N) {} My problem with the above? (1) seems too contrived while (2) seems redundant. I wanted to see if there's a better way to approach this - thanks for your suggestions.

I use huge data files, sometimes I only need to know the number of lines in these files, usually I open them up and read them line by line until I reach the end of the file I was wondering if there is a smarter way to do that

i trying to get data from this URL ( ). I looking for the data series, not the data in table and charts. This website have a button for download .csv, this .csv was enought for me, but i dont know how get it automatically in my javascript code. Thank you

I need to do an request in JavaScript. What's the best way to do that? I need to do this in a Mac OS X dashcode widget.

I have confused to uninstall python3 or fix my VPS Ubuntu Im using Ubuntu 16.04.5 LTS (GNU/Linux 4.4.0-31-generic x86_64) I tried to uninstall all python packages sudo apt-get purge python3 And getting this error dpkg: error processing package python3-pkg-resources (--remove): subprocess installed pre-removal script returned error exit status 127 Processing triggers for libc-bin (2.23-0ubuntu10) ... Errors were encountered while processing: python3-lxml python3-pip python3-apt python3-pyparsing gir1.2-ibus-1.0:amd64 hplip-data python3-blinker python3-bs4 python3-cairo python3-chardet python3-dbus python3-defer python3-feedparser python3-gi python3-guacamole python3-httplib2 python3-idna python3-jwt python3-louis python3-markupsafe python3-padme python3-setuptools python3-problem-report python3-ptyprocess python3-pyasn1 python3-pycurl python3-six python3-wheel python3-xdg python3-xkit python3-xlsxwriter dh-python python3 python3-pkg-resources E: Sub-process /usr/bin/dpkg returned an error code (1) I tried other way from other site,error still same And i tried to reinstall my ubuntu with command line apt-get install --reinstall ubuntu-desktop I dont know should i do to fix my ubuntu and reinstall my python. Note: I tried to run python3 it not working with reasons python3 is not package and i run python3.7 it working fine,idk python3.7 thats reall python package i have or something else :/ Im so appreciate any help

I am a new Ubuntu user running Ubuntu 13.04. I've been trying to install and use a DeDRM tool, but I've been having problems doing so. I was following some directions that said I needed a version of Python 2.7, but not anything Python 3.0 or later (because 3.0 versions are missing some necessary libraries?). I tried to install Python 2.7.5.6, but it didn't work. I thought it was probably because I had the later version of Python, so I went through terminal and removed Python 3.3, so I could install the earlier version of Python. Now that I've uninstalled Python 3.3, a lot of applications no longer work, including the terminal and the Ubuntu Software Center. I have no idea how to fix this problem now.

I saw this symbol: $\underline{\big|6} $ in a question bank for a chapter of permutations and combinations. I have included the question from the book to provide more context: .

Does anyone know where the factorial "!" symbol came from? I can't decide if it is my favorite or least favorite notation in mathematics...

I went to Italy with my husband last year (he is British and I am Indian and we live in the UK). I got a free spouse of an EU national visa for a year with multiple entries allowed, this was issued by the Italian consulate. So technically, I have a valid Schengen visa but in the annotations, it says 'free visa, EU family' (in Italian). Now I'm going to Spain with my sister in July and my husband can't join us. I know that according to EU law, I should apply for a new tourist visa. But will my existing Schengen Type C tourist visa cause any issues? I have read that you cannot have two Schengen visas at the same time. I am dreading the thought of getting visas canceled and chasing consulates for a short weekend trip. My questions are: If I apply for a Schengen visa with the Spanish consulate, will they ask me to cancel my existing Schengen (EU family)? Or should I go to Spain without my husband? It would help to know if anyone in this situation has been successful at changing their visa types or simply visiting the Schengen area without their spouse.

I have a Schengen visa (for five years) which states that I am a family member of an EEA national. I traveled, on this visa, with my spouse (UK citizen) to Croatia in May 2015 with no issues. However, now I wish to travel to Hungary without my spouse for a week but I am not sure if I will be allowed entry this time around into the country without my spouse. Do I have to produce any documents at the border since I am not traveling with my spouse? I plan to take a copy of my marriage certificate and my partner's passport copy anyway.

I am working on a data set that has 930 rows and 5 columns. I'm implementing KNN Regression with bootstrapping and my RMSE is almost 400 (depending on different cross validated outputs). I read and one of the answers mentioned that if the training and test RMSE are similar, then the model is good; any my training error is close to 400 too. I've tried searching online for reliable sources to know if this high an error rate is acceptable, but I've mainly read articles and posts that say the closer the RMSE is to 0, the better, which definitely is not the case here. Any advice is appreciated!

I've fitted my model and am trying to understand whether it's any good. I've calculated the recommended metrics to assess it ($R^2$/ AUC / accuracy / prediction error / etc) but do not know how to interpret them. In short, how do I tell if my model is any good based on the metric? Is an $R^2$ of 0.6 (for example) sufficient to let me proceed to draw inferences or base scientific/business decisions? This question is intentionally broad, to cover a wide variety of situations that members frequently encounter; such questions could be closed as duplicates of this one. Edits to broaden the scope beyond the metrics mentioned here are welcome, as are additional answers - particularly those that offer insight about other classes of metrics.

I know that if $({t\over p})=1$, then $t$ is a quadratic residue, which means that $x^2 \equiv t$ mod p has solutions. So is there any skills or methods that I can use to solve the equation given a prime $p$ and $({t\over p})=1$? Thanks a lot!

Given a prime $p$ and number $a$, how do I find the smallest $n$ such that $n^a\equiv 1 \pmod p$? Is there a non trial-and-error method? Edit: obviously removing $n=1$!

I have to import a number of text files into SQL Server tables, and some of the text files have columns where all the rows appear to be mostly, if not all, null values. Is there any simple way to write a query that will list all the columns in a table that have nothing but null values?

How do I select all the columns in a table that only contain NULL values for all the rows? I'm using MS SQL Server 2005. I'm trying to find out which columns are not used in the table so I can delete them.

I'll start by saying I tried everything I found. And still nothing worked. Preface I've converted my old MBR to GPT partition table. I actually thought I'll just have to reinstall GRUB2 and eventually Windows and it'll be fine. It wasn't. I used gdisk(GPT fdisk) to do the conversion without data loss. Problem At first, my Windows wouldn't load. Then, I'd do repair of BCD, where the problem was, and ended up not being able to boot to HDD at all and stuck at grub rescue screen. Tried full repair, and every other repair I run into, same thing. When I reinstall/repair GRUB, I get BCD error at windows boot. Solutions and further problems The most obvious one - reinstall Windows. Well, not gonna happen. It won't install on GPT without UEFI hardware. Protecting me from myself, so Microsoft-style. I made a terrible mistake and didn't realize the problem was at the partition TABLE, and not the partition itself, and formatted Windows partition. I didn't lose anything important - well, except Windows. Next thing I tried was hybrid-MBR. I guess no one told Windows installer that, since it gives the same error(tried windows 7 and 8 both 64-bit). I used gdisk recovery menu for that, and went through all the inputs, and finished working properly. Next was the attempt of DUET installation. Where I expected it to fail boot, due to my AMD CPU, it didn't even manage to install. I used duet-install script which I downloaded together with the files . The script stops always at the same spot: Partition starts at sector 2048. And I've looked at the script's source, it should soon print out next line(it printed 13 lines in a moment), but nothing happens, for hours. Tried re-running, re-downloading, running from live CD, and nothing. Here's the whole output: Will install SYSLINUX to the MBR Path to SYSLINUX is /usr/share/syslinux Path to bootduet is /home/ubuntu/Downloads/tianocore_uefi_duet_builds-tianocore_uefi_duet_installer/BootSector Path to UEFI DUET is /home/ubuntu/Downloads/tianocore_uefi_duet_builds-tianocore_uefi_duet_installer Will install UEFI version UDK Target partition is /dev/sda1 Will create a FAT filesystem called 'ESP' on the target partition Target disk (for storing MBR boot code) is /dev/sda Partition number is 1 Partition starts at sector 2048 [edit] Tried installing XP, but it can't format the unformatted space. I tried formatting it with GParted to ntfs, but installation still registers it as unformatted space(and nothing else except it). But to be completely honest - that cd was shelved for a long time, I barely found it, and I have no idea is it x64(probably isn't so not gonna work). So, I'm stuck now. Help please? Also, reformatting whole HDD isn't an option. Windows isn't worth it, I'd rather stay with Linux. Also, conversion back to MBR neither, since as far as I read, it includes formatting. Also, I got 7(or 8?) partitions(5 on old MBR, but I used extended partitions... was messy). Specs MoBo: ASUS M5A78l-M LX CPU: AMD Athlon II x3 450 Current Workaround (well, except the obious(linux)) I got windows 8 installation to start in VirtualBox. It's some progress, but I don't want to be stuck with VM every time I want to launch Windows. Edits I've played around with a duet-install script. If I type some letter and hit enter, it prints parted: invalid token: [letter]. If that letter is 'c', it prints Unknown partition table type ! Aborting!, which is obviously not the case. I guess I'll have to analyze the source deeper to get to the root of problem, because that script is the best solution to me now. Got to the point where script stops executing: ptLine=parted "${targetDisk}" print | grep "Partition Table"`. Will try to find a solution by skiping checks and set values to match my system. I have edited the script, and removed the part that didn't work, and finally manage to install DUET. Or at least it said so... I notice no changes to BIOS, it's all like on beginning. Still won't work.

I'd like to know if there's a method to get Windows 7 or Windows 8 Developer Preview to install to a GPT disk on my traditional IBM PC BIOS setup. Windows 7, of course, rejects my GPT partition, because I don't have UEFI. Well, Debian and Grub 2 seem to work fine... So I want to know if there's a way to force Windows to work as well. I'd seriously prefer avoiding hybrid MBR/GPT, because it's quite fragile and feels hackish, but it does work. I would assume the main blocker is that Microsoft is simply not adding support in their BIOS bootloader for GPT, which is understandable, I suppose. Is there any recourse? The way I see it, there are a few potential solutions: Having an alternate bootloader for the Windows kernel. NOT a chainloader. As far as I know, none exist. That's a shame. Storing as little as possible on an alternate MBR-based disk. Not liking this idea, but it's doable. I'm not sure I'd call this a solution to the problem as much as a workaround. Emulating EFI enough to get the EFI bootloader to work... I remember hearing a bit about a UEFI-on-BIOS emulator, but I can't find anything about it now. I assume this is doable, but there's probably not much demand for it yet, and it's probably no fun at all to setup. GRUB 2 seems to be able to boot a hackintosh with necessary EFI emulation, but I guess there's no interest/UEFI 2 is harder to approach (and I would assume other EFI emulators used for hackintosh are on the same boat.) Coreboot with TainoCore. Coreboot does not work on my motherboard (as far as I know,) and I'm quite sure the last effort to do this during GSoC was a failure. I'd absolutely love this solution, if it did work, though. Am I missing anything?

I don't know how to solve the following: Let $(x_n)_{n=1}^\infty$ be a sequence with property $\sum_{n=1}^\infty |\frac{x_n}{n}|<\infty$. Find a limit $\lim_{n\to\infty}\frac{x_1+x_2+\dots+x_n}{n}$. Any hint is welcome. Thanks in advance.

Suppose that the series $\sum \limits_{n=1}^{\infty}\dfrac{a_n}{n^{\sigma}} \quad(\sigma>0)$ converges. Prove that $\lim \limits_{n\to \infty}\dfrac{a_1+a_2+\dots+a_n}{n^{\sigma}}=0$. I applied the Abel transformation, but unsuccessfully.

I don't get why it is so hard to get my neural network to learn such a simple function. I've tried all sorts of combinations of layer numbers, number of neurons but it doesn't seem to want to learn. Any suggestions would be greatly appreciated! Here is my code: import numpy as np import numpy from tensorflow import keras from tensorflow.keras import layers import random inputs = keras.Input(shape=(1,)) dense = layers.Dense(50, activation="relu") x = dense(inputs) x = layers.Dense(50, activation="relu")(x) x = layers.Dense(50, activation="relu")(x) x = layers.Dense(50, activation="relu")(x) x = layers.Dense(50, activation="relu")(x) outputs = layers.Dense(1)(x) model = keras.Model(inputs=inputs, outputs=outputs, name="kinetic_energy") adam = keras.optimizers.Adam(lr=0.0002,beta_1=0.9, beta_2=0.999, epsilon=None, decay=0.0, amsgrad=False,) model.compile( loss='mean_squared_error', optimizer='adam', metrics=["mean_squared_error"], ) for j in range(10): x = np.array([]) y = np.array([]) for i in range(1000): randint = random.randint(0, 10000) square = randint * randint x = numpy.append(x, randint) y = numpy.append(y, square) model.fit(x, y, epochs = 100) x = np.array([20]) z = model.predict(x) print (z) ```

In spirit of the famous joke and I started to think, if it's possible to design a neural network that implements $y = x^2$ function? Given some representation of a number (e.g. as a vector in binary form, so that number 5 is represented as [1,0,1,0,0,0,0,...]), the neural network should learn to return its square - 25 in this case. If I could implement $y=x^2$, I could probably implement $y=x^3$ and generally any polynomial of x, and then with Taylor series I could approximate $y=\sin(x)$, which would solve the Fizz Buzz problem - a neural network that can find remainder of the division. Clearly, just the linear part of NNs won't be able to perform this task, so if we could do the multiplication, it would be happening thanks to activation function. Can you suggest any ideas or reading on subject?

I want to get a particular table's primary key using SQL query for SQL Server database. In MySQL I am using following query to get table primary key: SHOW KEYS FROM tablename WHERE Key_name = 'PRIMARY' What is equivalent of above query for SQL Server ?. If There is a query that will work for both MySQL and SQL Server then It will be an ideal case.

Simple question, how do you list the primary key of a table with T-SQL? I know how to get indexes on a table, but can't remember how to get the PK.

Can Ubuntu be used in a computer with no internal hard drive? Using only a USB or external hard drive

When I create a bootable USB stick (Ubuntu) on Windows, does it mean that the changes that I will do (let's say save a new file called "abc.txt" on the Ubuntu desktop) will those changes be reflected the next time I boot this USB on some other computer (I will see the file "abc.txt" on the Ubuntu desktop)? Next one might be a pretty stupid question but here it is: Will it use the computer's RAM or use the space left on the USB as RAM. Thanks

I once heard it suggested that using multiple smaller memory cards was a good way to decrease the chances of losing data. It's hard to argue with the logic that several memory cards are unlikely to fail all at once but reality is complicated and there could be reasons that this advice is either unimportant or maybe even harmful. How does this pan out in reality? Is the rate of failure of major brand memory cards high enough for this to be a realistic concern? Handling a larger number of small memory cards could increase the chances for human error. Am I likely to come out ahead with smaller memory cards?

I don't think anyone can give a definitive answer, but what are the factors I should consider? What are the pros and cons? I'm thinking: What are the costs? the risks? How is usability affected? Anything else? Can you give any concrete examples or experiences you have had which incline you one way or the other? Any thoughts gratefully received.

I am trying to access a node defined inside a pic definition outside its scope. I found this example in the PGF manual v3.0.1a on page 254. The example given is as follows. \documentclass{standalone} \usepackage{tikz} \begin{document} \tikzset{ seagull/.pic={ % Code for a "seagull". Do you see it?... \coordinate (-left wing) at (-3mm,0); \coordinate (-head) at (0,0); \coordinate (-right wing) at (3mm,0); \draw (-left wing) to [bend left] (0,0) (-head) to [bend left] (-right wing); } } \tikz { \pic (Emma) {seagull}; \pic (Alexandra) at (0,1) {seagull}; \draw (Emma-left wing) -- (Alexandra-right wing); } \end{document} But I get an error on compiling: No shape named EmmaEmma-leftwing is known. Does anyone know what's wrong in this code and how one can access nodes defined inside a pic outside their scope.

I read instruction how to use \pic in PGF 3.0.0 manual, but description how to give names to \pic are not clear to me and given example generate error: "No shape named EmmaEmma-left is known." Example in manual (pp. 255): \documentclass[tikz,border=3mm]{standalone} \tikzset{ seagull/.pic={ % Code for a "seagull". Do you see it?... \coordinate (-left wing) at (-3mm,0); \coordinate (-head) at (0,0); \coordinate (-right wing) at (3mm,0); \draw (-left wing) to [bend left] (0,0) (-head) to [bend left] (-right wing); } } \begin{document} \begin{tikzpicture}%\small\sffamily \pic (Emma) {seagull}; \pic (Alexandra) at (0,1) {seagull}; \draw (Emma-left wing) -- (Alexandra-right wing); \end{tikzpicture} \end{document} It's obvious that something is missing in above example. Please enlighten me, what I missed.

My class implements a very simple prototype of an RPN calculator. The following construct isn't working. Why? What am I doing wrong here? public boolean executeCommand(String command) { if(command == "+") { add(); return true; }else if(command == "-") { subtrair(); return true; }else if(command == "*") { multiplicar(); return true; }else if(command == "/") { dividir(); return true; }else { System.out.println("The command does not exist."); return false; } } The output is always, no matter what the string contains, The command does not exist. Why? I really don't get it! If someone could please explain, I'd be thankful! In more detail The method in question is: public boolean executeCommand(String command) { Scanner str = new Scanner(command); if (str.hasNextDouble()) { dataStack.push(str.nextDouble()); return true; } else { System.out.format(" DEBUG: command: %s$%n", command); if(command == "+") { add(); return true; }else if(command == "-") { subtract(); return true; }else if(command == "*") { multiply(); return true; }else if(command == "/") { divide(); return true; }else if(command == ".") { print(); return true; }else if(command == ".s") { showStack(); return true; }else if(command == "exit") { exit(); return true; }else { System.out.println("The command does not exist."); return false; } } } which, for any input I threw at it, (except for numbers, of course), resulted in: DEBUG: command: [COMMAND HERE]$ The command does not exist. Source code I removed some irrelevant source code; (i.e. some methods, package name) but it is still compilable and runnable: import java.util.Scanner; import java.util.LinkedList; public class RPNCalculator { public static void main(String[] args) { RPNCalculator calc = new RPNCalculator(); calc.startInteractiveMode(); } protected Scanner scanInput; public LinkedList<Double> dataStack; protected boolean interactiveModeEnabled; public RPNCalculator() { scanInput = new Scanner(System.in).useDelimiter("\\s+"); dataStack = new LinkedList<Double>(); } public String getCommand() { return scanInput.next(); } public boolean executeCommand(String command) { Scanner str = new Scanner(command); if (str.hasNextDouble()) { dataStack.push(str.nextDouble()); return true; } else { System.out.format(" DEBUG: command: %s$%n", command); if(command == "+") { ommitedOp("add"); return true; }else if(command == "-") { ommitedOp("subtract"); return true; }else if(command == "*") { ommitedOp("multiply"); return true; }else if(command == "/") { ommitedOp("divide"); return true; }else if(command == ".") { ommitedOp("print"); return true; }else if(command == ".s") { ommitedOp("showStack");return true; }else if(command == "exit"){ ommitedOp("exit"); return true; }else { System.out.println("The command does not exist."); return false; } } } public void startInteractiveMode() { interactiveModeEnabled = true; while (interactiveModeEnabled) { String command = getCommand(); executeCommand(command); } } public void ommitedOp(String method){ System.out.println("Command exists!"); } }

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug. Is == bad? When should it and should it not be used? What's the difference?

I am trying to make a spotlight illuminate a scene. I have removed the linked background so that there is no ambient light but the following render depicts this spotlight at about a strength of 4.5 million. Any ideas of how it got like this and how to get it to a normal range?

recently, I was using mesh planes to emit some light, and they had a strength of 8.0.. this worked well now, I want to swap these out for area lamps (to improve performance) i've positioned these area lamps in the place of my emitter polygons i've scaled them such they have 1.0 transform scale, and in the lamp settings, I set the size to 1m across (to size-match the previous emitters) the problem is, the lamps require a crazy "strength" of at least 1 000 000 (one million!) to produce any reasonable amount of light... this seems bonkers! point lamps, area lamps, and the others, are all effected my scene is scaled using the Centimeters preset.. the foreground is only a meter a way, and the more distant background is more like 5 meters back i've paid special attention to the sizing and scaling of this scene, I can't figure out why the mesh emitters are working with a sane Strength of 8, and the lamps require something out of this world? something must not be right... Edit: Remastered scene corrects scales, problem persists i've remastered the scene so that all of the objects have a proper scale factor of 1.0 this should correct any sizing discrepancy/confusion my scene must be in centimeters preset, all my other work is in centimeters the area lamp size is now definitely 1m, as highlighted in the above screenshot (and it is not affected by the 1.0 transform scaling factor, also highlighted (I also verified the delta scale is also 1.0)) despite correcting the scaling of my scene, strength 1 000 000 is still required is blender simply not accounting for my scene's Unit Scale setting?

I want to play in the same house against friends in GTA online. I have an Xbox one and xbox 360 but only have game for xbox 360. If I get the game for xbox one can we play together using same wifi and in same channel with people and complete races, deathmatches, missions, etc. together?

Grand Theft Auto Online exists on five different platforms: XBox 360, PS3, XBox One, PS4, and PC. Do any of these play on the same servers, allowing people on differing platforms to play together?

I want to extract an exact line from a very big file. For example, line 8000 would be gotten like this: command -line 8000 > output_line_8000.txt

Say I have a huge text file (>2GB) and I just want to cat the lines X to Y (e.g. 57890000 to 57890010). From what I understand I can do this by piping head into tail or viceversa, i.e. head -A /path/to/file | tail -B or alternatively tail -C /path/to/file | head -D where A,B,C and D can be computed from the number of lines in the file, X and Y. But there are two problems with this approach: You have to compute A,B,C and D. The commands could pipe to each other many more lines than I am interested in reading (e.g. if I am reading just a few lines in the middle of a huge file) Is there a way to have the shell just work with and output the lines I want? (while providing only X and Y)?

I tried to align the equation and have some text on the equal sign. But it turns out that the equal sign that has text over it is no longer aligned to previous one anymore (I believe it is the text "ccc" that is aligned). How do I fix the problem to let the equal sign aligned but not text over it? \begin{equation} \begin{split} a &= b \\ &\overset{ccc}{=}d\\ &= e\\ \end{split} \end{equation}

Look at the following example \begin{align} & x \\ \overset{\text{some long explanation}}= & foo \\ & = bar \end{align} what is the best way to get the equal signs aligned? Now I have seen different solution such as adding \overset{\hphantom{\ţext{some long explanation}}}= to the beginning of every line, but I don't really think that is the best solution. Any better ideas? UPDATE I guess what i am actually after is aligning the first column of the align environment right aligning the equal sign under the overset text right

Hey!! So a few years ago, an old man gave me this bmx but it was very old so me and my dad decided to fix it. The seat is new and so are the tires. The rest is all original, could someone help me? I have never seen this type of frame tho, it has an "X" on it, as you can see

We often get questions on bicycles.stackexchange about identifying a bicycles manufacturer, model, make, and year. Often these questions are downvoted or closed -- usually with a comment attached to them that it's not necessary to know the exact model/make/year of a bicycle if you want to fix, repair, or ride your bike. Why should owners not care about the model/make/year of their bicycle? Especially when it comes to less expensive bikes (aka BSOs) and BMX bicycles? This is intended as a canonical question that we can point closed questions to. Also see (generally not helpful for identifying a brand/model)

Let $\{a_n\}$ be a sequence of real numbers such that $$\lim_{n \to \infty} \mid a_n + 3(\frac{n-2}{n})^n \mid^{\frac1n} = \frac35$$ Then find $\lim_{n \to \infty} a_n$. Tried very hard yet not able to crack it. Help Needed. Anyone able to do the sum??

Let $\{a_n\}$ be a sequence of real numbers such that $$\lim_{n \to \infty}\left|a_n+ 3\left(\frac{n-2}{n}\right)^n \right|^{\frac{1}{n}}=\frac{3}{5}.$$ What is the value of $\lim_{n\to \infty} a_n$?

I'm using sfdx force:source:retrieve -m Profile what returns is a list of profiles but only the userPermissions, none of the object permissions or other things.

Problem The <objectPermissions> tags are missing from my custom profiles when I pull from a scratch-org using SFDX or MDAPI. Steps to reproduce Create a new Scrach-org. Create a custom profile, say "Support". Add some Standard Object Permissions to the profiles. Looks like this: Use SFDX pull or MDAPI Retrieve. The Support.profile-meta.xml contains all the settings I added to the profile, except for <objectPermissions>. The missing tag should look like this: <objectPermissions> <allowCreate>true</allowCreate> <allowDelete>true</allowDelete> <allowEdit>true</allowEdit> <allowRead>true</allowRead> <modifyAllRecords>true</modifyAllRecords> <object>Account</object> <viewAllRecords>true</viewAllRecords> </objectPermissions> If I now push the profile to a new scratch org, then the profile will be missing some permissions such as View All and Modify All since the tags are missing. Looking like this: Questions How can I use SFDX or MDAPI to retrieve the missing tags? Or, do some workaround exist?

I am an Australian flying from Brisbane, Australia to Bogota, Colombia. I have 2 stop-overs en route on Saturday the 19th - one in LA, the next in Atlanta. Both are only 2hrs. Because the flight from LA to Atlanta is domestic I must pass through customs and immigration in LA, then the reverse in Atlanta. I understand 2hrs is possible (I'm only taking carry-on luggage), but cutting it fine. Should I be concerned that the US government shut down might create further delays?

My grandparents bought a flight on United Airlines that departs on Feb 10 2019, as the one and same ticket, from Toronto, to ORD with 1 55-minute layover, then Maui. Please ping me if I ought post their return flight on Feb 24's details. advises: There should be no customs and immigrations formalities at ORD, as YYZ is a , and CBP matters will be handled in Toronto. I'm assuming that persists during their vacation to Maui. reported some TSA agents' refusal to work. Will refuse to work, or any other federal workers pertinent to travelling to and from the US?

The title says it all. I haven't been able to find the answer yet, so any help would be appreciated.

I've heard that you should use \[ ... \] for displayed equations instead of $$ ... $$, but why is that? I'd assumed that it's so that you can more easily tell which are starting and which are ending delimiters, but if I always use a syntax-highlighting text editor, I can see that easily based on the color of the symbols. Is there any reason for this suggestion?

Just recently upgraded to 13.04 and am having trouble running TF2 via Steam. Whenever I start Steam I get a dialog saying: OpenGL GLX context is not using direct rendering, which may cause performance problems. Every time I go to launch TF2 I get a dialog saying: Could not find required OpenGL entry pint 'glGetError'! Either your video card is unsupported, or your OpenGL driver needs to be updated. I tried updating my Nvidia drivers, hoping that would solve this issue but alas, it did not. I believe this issue is related to a fix I used to get Skype working with 13.04, specifically . Just a heads up I'm using GNOME Shell 3.8. Let me know if you need anymore information about my system.

I am not able to play "Half-Life-2" on Steam + Ubuntu 14.04 . Error shown in message box on screen: Could not find required OpenGL entry pint 'glGetError'! Either your video card is unsupported, or your OpenGL driver needs to be updated. I have a Dell Inspiron Laptop. My OS is Ubuntu 14.04 and my graphics card is AMD Radeon HD 8600M. I have installed AMD properietry Driver. The partial output of "glxinfo" is as follows: name of display: :0 libGL: screen 0 does not appear to be DRI3 capable libGL: pci id for fd 4: 8086:0a16, driver i965 libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/i965_dri.so libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/i965_dri.so libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory. libGL error: failed to load driver: i965 libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/tls/swrast_dri.so libGL: OpenDriver: trying /usr/lib/i386-linux-gnu/dri/swrast_dri.so libGL: driver does not expose __driDriverGetExtensions_swrast(): /usr/lib/i386- linux-gnu/dri/swrast_dri.so: undefined symbol: __driDriverGetExtensions_swrast libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory. libGL: Can't open configuration file /home/arushi/.drirc: No such file or directory. libGL error: failed to load driver: swrast display: :0 screen: 0 direct rendering: No (If you want to find out why, try setting LIBGL_DEBUG=verbose)

In this particular case the reset command. I want to read the code of this command. TY

I'm answering a question with a suggestion to use rename, and I realize I don't know what package it comes from (as part of the answer, I imagine saying something like "if you don't have rename, it's installed as part of [package]"). man rename tells me to SEE ALSO: mv(1), perl(1) - so my first thought is that it was installed with perl. A related answer, , helps me figure out that the perl package includes prename but not rename - and it turns out that my /usr/bin/rename points to /etc/alternatives/rename which points to /usr/bin/prename So this is still kind of confusing. Did /etc/alternatives/rename point somewhere else before I installed perl? Is there a general way to tell which package something comes from?

Whats the difference between defining the method "area" as a property of "this" instead of "prototype"? //console.clear() function Rectangle(w, h) { this.width = w; this.height = h; this.area = function( ) { return this.width * this.height; } } var r = new Rectangle(2, 3); var a = r.area( ); //console.log(a) function Square(s) { this.side= s; } Square.prototype.area = function(){return this.side * this.side; } var r = new Square(2); var a = r.area( ); //console.log(a) In JavaScript - The definitive guide in the section Prototypes and Inheritance of Chapter 9 , part 1, the author says that defining the method "area" inside the prototype object is beneficial, but his explanation wasn't really understandable: "..the area of every single Rectangle object always refers to the same function (someone might change it, of course, but you usually intend the methods of an object to be constant). It is inefficient to use regular properties for methods that are intended to be shared by all objects of the same class (that is, all objects created with the same constructor)." I know this question almost looks like one, but it is not.

What's the difference between var A = function () { this.x = function () { //do something }; }; and var A = function () { }; A.prototype.x = function () { //do something };

class Student{ public **static** void main (String[]arg){ } } Here why we are using static keyword to start a main method. From my knowledge I can say Static will get memory and it can retain its value Is that only reason for using Static key work in main. Explain in detail thanks .

The method signature of a Java main() method is: public static void main(String[] args){ ... } Is there a reason for this method to be static?

Javascript says 0.7-0.2 is equal to 0.49999999999999994. The case is the following: var change = 0.7 - 0.2; switch (change) { if (change.toFixed(2) >= 1) { ... } else if (change.toFixed(2) >= 0.50) { ... } else if (change.toFixed(2) >= 0.20) { ... } ... } By using .toFixed() method, the problem is solved but is there another way, instead of using .toFixed() n-times;

Consider the following code: 0.1 + 0.2 == 0.3 -> false 0.1 + 0.2 -> 0.30000000000000004 Why do these inaccuracies happen?

I took this shot using a Sony Xperia SP with OpenCamera, here are some details: Exposure: 1/800 ISO: 50 Aperture: f/2.4 focal length: 3.0 The photo was taken out of a train, at around 160km/h, the truck was moving in the opposite direction with approx. 90km/h. The distance that the truck moved withing the 1/800th of a second should be somewhere around 10cm (~1/3 foot), but the distortion is clearly higher. It also does not look like it's related to the lens distortion as the it's speed dependent (look at the car and guardrail as a reference). looks similar and is caused by line-wise image creation of a crt-tube. Could it be that the sensor is reading the pixels line-wise as well? Almost forgot the most relevant detail: the shot was taken on the Storebæltsbroen. ;-)

In answer to , Adam Davis writes: Your camera complicates this by using a rolling shutter above a given speed (usually around 1/200. This means that only a portion of the image sensor is exposed to the scene at any given time, so if the light changes during the exposure, the color change will only affect a portion of the image sensor. Rolling shutters often are also mentioned in the . However, I am yet to see a discussion of what a rolling shutter is, how it works and when it is important. What is a rolling shutter? What are the implications of using one for my photos?

I am a bit puzzled by this myself. If for some reasons I would like to encode any valid url into valid pathname, say, to be used on an image proxy with an url structure like: http://image-proxy/hash_of_url/encoded_url Is there an efficient way to achieve encoded_url in javascript? I am on node.js runtime. I need to do this because it would be used by another proxy not in my control, which had problem with an url like this: http://image-proxy/hash_of_url/?url=encoded_url PS: hash_of_url is a hmac digest of original url, to ensure url is generated by server, but that's not important to my question.

How do you safely encode a URL using JavaScript such that it can be put into a GET string? var myUrl = "http://example.com/index.html?param=1&anotherParam=2"; var myOtherUrl = "http://example.com/index.html?url=" + myUrl; I assume that you need to encode the myUrl variable on that second line?

My machine is not an Internet connected. So I mounted the ISO image and installed some packages. If I want to INSTALL GDB and some other packages how should I install in the machine?

I have a friend who has got a computer that is not connected to the Internet. Is there any way to install software offline easily?

I am a beginner to QGIS. My problem is I tried to create sub-catchment within a basin by using provided point datasets (river gauge location). In total, I have 12 measuring points (i.e 12 pairs of x and y coordinates) within my basin. I want to delineate all catchments within basin on the basis of provided coordinates ( not on the basis of minimum or maximum cell that r.watershed has.) I am looking for the function in 'hydrology' extension tool of ArcMap.

I am using qgis 2.14.17 with ubuntu16. Having as input data a DEM of the region and a river network. In the manual of qgis they suggest to use a toll of qgis: Catchment area (Parallel); I dont have this in my toolbox, anybody made the same experience and could tell me the reason for it and how to get it. It seems to offer the best solution for me. Tools which are available are from GRASS7 and TauDEM, the latter need much more data it seems. And I am not sure if I am able to create these just out of a DEM? The GRASS7 has one tool r.water.outlet: but here one has to put the outlet coordinates, which clearly I could get out of the river network, but the idea is that they are generated by delineating the watersheds. Somebody has an idea how to solve it? I managed now to get SAGA run in the toolbox, nevertheless would be great if somebody could help me with the qgis tool, since it should appear?!

I started talking with a guy and got into a sugar baby arrangement with him. He offered to pay off my credit card and pay me $800/weekly. I never gave him my bank info or anything related to me, but he gave me his bank info (account and routing number, etc). He asked me to go to the store to buy $900 worth of gift cards for 3 separate customers, which I stupidly did... I then spent the weekend arguing with him because he wanted me to buy more gift cards for customers, but I continuously refused because the money that was transferred hadn't hit my account yet so I didn't have any money. I contacted my bank this morning to let them know that the money was going to be transferred, but I wanted to make sure that I was taking every precaution since it was a large sum of money. I asked her to contact the guys bank and see if there were sufficient funds in the account so it wouldn't bounce and there were. The money finally reached my credit card today but I don't want to use my card at all until I know what is truly going on.

I met a guy on a sugar daddy dating site and we talked, I told him my situation and he said he would help. He asked for my bank account information and I told him you can use cash app or PayPal to go through. He said his account manager deals with his finances. So I set up an account with a bank that I don’t use so that my primary account isn’t used. Eventually he was in the process of sending me money and we had agreed on a amount that wasn't crazy. But then he asked for my address and I asked why and he said just wondering. Then said he wanted to send me a surprise for being his baby. Which I didn’t give. Then later on he sent the money and said he sent me a bonus and that I was supposed to use that to pay his mothers caregiver, which he didn’t mention until after. I kept questioning him and he was saying that he works in construction and he’s trusting me to carry out the errand. Then he said don’t let him down and I asked him if he was threatening me and he kept saying I need this done but didn’t really answer my question. Am I being scammed? I’m about to change my password but is this a scam?

I have got a shapefile consisting of a number of polygons, and another shapefile with a number of points. I want to add a column in the points shapefile. For each point, I want the column to contain the name of the polygon that surrounds it. In simple terms, I just want to find out to which polygon each points belongs to. Any tips? Here is the screenshot:

I have two feature classes, a polygon of sales areas for a city, and point layer of addresses. I want to select the addresses based on the sales area they are in and update their attribute table to show the sales area. I have searched python+point+in+polygon for other posts and I know how to select the polygons but I can't figure out how to populate the address points. I found the following script that works but takes almost two hours to run. import arcpy import os # Allow overwrite arcpy.env.overwriteOutput = True # Script user input parameters polygonLayer = arcpy.GetParameter(0) pointLayer = arcpy.GetParameter(1) workspace = arcpy.GetParameter(2) copyField = = arcpy.GetParameterAsText (3) # Add new field to target feature class fieldList = arcpy.ListFields(pointLayer) fieldNameList = [] for field in fieldList: fieldNameList.append(field.name) fieldType = arcpy.ListFields(polygonLayer,copyField)[0].type if not copyField in fieldNameList: arcpy.AddField_management(pointLayer, copyField, fieldType) arcpy.MakeFeatureLayer_management(polygonLayer, "PolygonLayer") pntCursor = arcpy.UpdateCursor(pointLayer) for pnt in pntCursor: rowID = pnt.OBJECTID arcpy.MakeFeatureLayer_management(pointLayer, "PointLayer", '"OBJECTID" = ' + str(rowID)) # Polygon selection based on CONTAINS selection method arcpy.SelectLayerByLocation_management("PolygonLayer", "CONTAINS", "PointLayer") # Copy field values from polygon to point layer polyCursor = arcpy.SearchCursor("PolygonLayer") for poly in polyCursor: pnt.setValue(copyField, poly.getValue(copyField)) pntCursor.updateRow(pnt) arcpy.Delete_management("PointLayer") del pntCursor, polyCursor, pnt, poly I don't think I need to create a new field so I have simplified my script too: # Import arcpy module import arcpy import os # Allow overwrite arcpy.env.overwriteOutput = True # Script user input parameters polygonLayer = arcpy.GetParameter(0) pointLayer = arcpy.GetParameter(1) workspace = arcpy.GetParameter(2) fsaPoly = arcpy.GetParameterAsText (3) #FSA in FSA_Boundaries fsaPnt = arcpy.GetParameterAsText (4) #FSA in Addresses # Select all Address in FSA polyCursor = arcpy.SearchCursor("PolygonLayer") for poly in polyCursor: # Select based on CONTAINS arcpy.SelectLayerByLocation_management(poly, "CONTAINS", "PointLayer") # Add FSA to Address pntCursor = arcpy.UpdateCursor("pointLayer") for pnt in pointCursor: pnt.setValue(fsaPnt, fsaPoly) pntCursor.updateRow(pnt) del pntCursor, polyCursor, pnt, poly I know my update cursor is wrong but i'm stuck on how to update one feature class using information selected from the other. I know I can do this manually but I need to do it for multiple cities so I would like to automate the process. I am using Arc 10.2.2 to run my python script.

I have a question, which may seem strange. I checkout some source code from SVN. However, for some reason I do not want this source code to be controlled by SVN. Are there methods to make it look like independent code without being controlled by any source control software. By the way, I am using Tortoise SVN in windows.

I have a folder, c:\websites\test, and it contains folders and files that were checked out from a repository that no longer exists. How do I get Subversion to stop tracking that folder and any of the subfolders and files? I know I could simply delete the .svn folder, but there are a lot of sub-folders in many layers.

Is it possible to move a to-do list from one card to another? It seems difficult even to copy/paste the list.

I often need to consolidate (combine) Checklists from a couple of Cards into one Card. Any way to do this?

I have been told that having a published review article is viewed as an advantage for higher education. The topic of my review article is the impact of information technology on the practice of human resource management. What are the sequential steps that I have to follow to make my review article acceptable to renowned publishers and university graduate professors? I have heard that to make a review article acceptable, the first task is to read vastly about the subject related topic of review article. After reading extensively, how can I proceed - I mean how can make linkage of writing in every parts of review article? Is it necessary to make a comparison, to find a gap or limitations,similarity of the previous primary and review articles on the same topic in writing my review article? Do I have to present the information about what others authors have done or shown? or do I have to include my own thought, ideas, decisions along with the other scholars?and if I intend take some information,graph from copyrighted books,will I need to take permission from real authors or just paraphrase the information on own my words?

I want to write a survey on one emerging research topic in wireless communications (It can be applied to any field!). There are almost 500 papers on this topic as published or in early access. And the publishing rate in this topic is increasing day by day. So, I want to write a survey on this topic keeping in mind that it will get high citation and it will help new scholar who are in struggle with this topic. I found only one survey written by some reputed authors, however it lacks in many ways, like detailed information related to particular direction, it just assembles the papers in a good manner. I want to pick some directions and discuss important approaches with good connection between them. However, I find it very difficult to proceed with large number of papers. Is there any good way to handle the survey process in a good efficient and quick way? PS. According to me, many people have already started to write this.

Stupidly, I upgraded my ancient laptop to 13.04 and am now in a world of slowness. I'm running in dual-boot mode alongside Win XP. I've seen other similar requests and the answer is reinstall. My question is how? I've put my 12.04 cd in and it boots ok and asks me if I want to install but then just hangs.

I just installed a new version of Ubuntu and I want to roll it back to the previous version. How can I do that? Is that even possible?

I choose option show the menus in the window's title bar. It works probably if I run an app in normal way, mean click on icon to open., but when I open it in terminal with root permission, the menu bar is no longer in title bar, it's in "a new part" (I think so) under the title bar. Gedit and more are the same.

Why do applications like synaptic (and other that need root privilege) have their menus in the window instead of top panel? Is it going to change or will it stay like that to indicate that user is on root privileges?

i want to install openssh from source on Ubuntu. i downloaded the source ./configure make sudo make install but with this last command, i get the following error: (cd openbsd-compat && make) make[1]: Entering directory '/home/pc/Desktop/openssh-7.6p1/openbsd-compat' make[1]: Nothing to be done for 'all'. make[1]: Leaving directory '/home/pc/Desktop/openssh-7.6p1/openbsd-compat' ./mkinstalldirs /usr/local/bin make: execvp: ./mkinstalldirs: Permission denied Makefile:313: recipe for target 'install-files' failed make: [install-files] Error 127 What can i do please to fix this error ? i can't find a solution !

I'm trying to install llvm. I cloned the repository and ran ./configure. Now, I need to run sudo make install. When I run this, I get the following errors: harshilsharma63@ubuntu:~/llvm$ sudo make install [sudo] password for harshilsharma63: llvm[0]: Installing include files make: execvp: /home/harshilsharma63/llvm/autoconf/mkinstalldirs: Permission denied make: *** [install-local] Error 127 harshilsharma63@ubuntu:~/llvm$ sudo make install llvm[0]: Installing include files make: execvp: /home/harshilsharma63/llvm/autoconf/mkinstalldirs: Permission denied make: *** [install-local] Error 127 I have installed build-essentials. I cloned the repository using svm in fedora and copied the downloaded files from Fedora -> Windows -> Ubuntu. Note: I'm using Ubuntu 12.04

Let $F$ is a field, and $R = M_n(F)$. Prove that (i) Every minimal left ideal of $R$ are isomorphic to each other (ii) Prove every simple $R$-module are isomorphic to each other I have if $M$ is a simple $R$-module, then there is a maximal left ideal $I$ of $R$ such that $M \cong R/I$. Now the big problem of mine is that I can't determine how the maximal ideal of $R$ look like? Why $R$ is semi-simple?

I've a basic question. $R$ is a simple left artinian ring. I want to show that all simple left $R$-modules are isomorphic. A simple $R$-module $M$ is isomorphic to $R/J$ where $J$ is a maximal left ideal of $R$. Does this imply that $M\cong Ra$ for some $a\in R$, $a\neq 0$? Many thanks.

Could anyone help me solving the following limit? $\lim_{n\rightarrow \infty} (\frac{1}{n+1}+ ... +\frac{1}{2n})$ I think it should just be 0 since we can distribute the limite inside the sum, but I am not sure of this answer. Thanks so much for your help!

Show that $$\lim_{n\to \infty}\left(\frac{1}{n+1}+\frac{1}{n+2}+\cdots+\frac{1}{6n}\right)=\log 6$$ Here I need to use the definition of integral but I faced problem in range . Please help.

Its just a problem with installing the printer from Epson using the configure printer program. It just freezes half way through instillation. I've been working on this problem or ages now I've tried everything from un-installing Software centre and Configure Printer programs. Each time it just stalls, then when I look in Software centre i can see packages half way installed. I've ran every script I can get my hands on. What is the command to find what the problem/error is? It started when I accidentally rebooted half way through its original install Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable) E: Unable to lock directory /var/lib/apt/lists/ once I clear this problem it occurs again when I try and Install the printer.

I just installed Ubuntu 13.10, and I can't configure my wi-fi Epson TX430W printer. Using the Settings->Printers interface, I can detect the printer. When I click add, I briefly see a "Searching for drivers" dialog. It dissapears, and then I'm left with the printer forever in "Installing" status. If I close the window and reopen Printers, it doesn't show up on the list. How can I solve, or at least diagnose the problem?

I have been reading a lot about the subject, I've seen lots of videos (youtube, udemy) and even read some scholar papers about it and everyone explains the above in so many different ways. We all know what the scientific definition of what voltage is but I still don't know what effect it has on the electrons. The water analogy which is used so much, seems to fail when we compare higher voltage vs lower voltage, because the higher the pressure of water in a tank is, the faster the water current will be once the tap is open, but the same does not apply to electrons. In fact, from what I've read, the velocity at which electrons move (drift velocity) is quite slow - small drift changes which propagate across the wire is what allow the fast delivery of electricity. The other thing I have a problem is is how the voltage is represented in a circuit. I keep reading over and over again and seeing in the water analogy too, that voltage is what pushes the electrons, but if that's the case why is voltage lower at the negative terminal? If I put a few springs in a box and apply pressure to close the box, some springs will contract and will probably fly away once I open the box, so using this analogy, is voltage the force necessary to keep the springs tight in the box? The electrons don't really need a push to move across the hire, they have that desire, they are attracted to the positive side, how what is really the voltage role here? Using another analogy, it seems that voltage is to electrons what fuel is to my car. At the end of a working day all I want to do is to drive home. I will always have the desire to reach home, but if I don't have enough fuel in the tank, I will never be able to, in the same manner, if there's no enough voltage the electrons will never reach the other end of the hire, even if that's all they want. To me, it seems that voltage is simply the force that pushes electrons apart from each other. I also see in so many videos, electrons flowing from the beginning of the circuit to the end, when in fact the electrons barely more. The more I read the more confused I become. UPDATE 1 This is the best explanation I have read so far: "A voltage appears whenever there is an imbalance of electrical charge (i.e. electrons). Since like charges repel and opposite charges attract, any collection of electrically charged particles creates some kind of force on each other. If there is an imbalance of negative to positive, a kind of "pressure" or "push" is formed. In conducting materials, electrons are free to flow through the material, as opposed to being fixed in atoms, and will therefore flow to the point of least "pressure"."

Bit of a strange question, but what is it? My physics teacher said it was kind of like a "push" that pushes electrons around the circuit. Can I have a more complex explanation? Any help is much appreciated.

Why am I getting "uses unchecked or unsafe operations" error everytime i compile? What's wrong with the code? I copied the exact same code from this tutorial import java.io.FileWriter; import java.io.IOException; import org.json.JSONArray; import org.json.JSONObject; public class JsonSimpleExample { public static void main(String[] args) { JSONObject obj = new JSONObject(); obj.put("name", "mkyong.com"); obj.put("age", new Integer(100)); JSONArray list = new JSONArray(); list.add("msg 1"); list.add("msg 2"); list.add("msg 3"); obj.put("messages", list); try { FileWriter file = new FileWriter("c:\\test.json"); file.write(obj.toJSONString()); file.flush(); file.close(); } catch (IOException e) { e.printStackTrace(); } System.out.print(obj); } }

For example: javac Foo.java Note: Foo.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details.

Hi I'm working on my scholarship exam practice but I got stuck at my last question, could you please have a look? I'll write every part of question so you know the big picture. I have marked the problematic question in bold below. This question only assumes knowledge in high school or pre-university level. Draw a circle $C$ on a plane. Put $n$ distinct points on the circumference of $C$. Join any two of the $n$ points with a chord. Suppose that no three chords intersect at any one point inside $C$. Let $c_n$ be the number of such chords, $i_n$ that of intersections of the chords inside $C$, and $r_n$ that of regions in $C$ bounded by an arc and/or some chords. Fill in the blanks with the answers to the following questions. (1) Find $c_1, c_2, c_3, c_4, c_5, c_6$ and write their values in this order. The answer of this part checked with answer key is $0, 1, 3, 6, 10,$ and $15$ by drawing 6 different circles with n dots from 1 to 6 each circle, connecting each dot and counting number of chords. (2) Find $i_1, i_2, i_3, i_4, i_5, i_6$ and write their values in this order. The answer of this part checked with answer key is $0, 0, 0, 1, 5,$ and $15$ by counting intersections of chords. (3) Find $r_1, r_2, r_3, r_4, r_5, r_6$ and write their values in this order. The answer of this part checked with answer key is $1, 2, 4, 8, 16,$ and $31$ by counting the regions. (4) Express $r_n$ with binomial coefficients in terms of $n$. (For binomial coefficients ${m}\choose{k}$, note that ${m}\choose{k}$$= 0$ if $m<k$.) I got stuck at this question since I got nowhere near the answer key. My approach is below: ${n}\choose{k}$$=\frac{n!}{(n-k)!\cdot k!}$ Pick $n=2$ and $n=3$ and substitute the values from (3) into the equation, ${2}\choose{k}$$=\frac{2!}{(2-k)!\cdot k!}=2$ ${3}\choose{k}$$=\frac{3!}{(3-k)!\cdot k!}=4$ $\frac{2!}{(2-k)!\cdot k!\cdot2}=\frac{3!}{(3-k)!\cdot k!\cdot4}$ And $k$ will be weirdly equal to $\frac{3}{2}$ leading to binomial coefficient ${n}\choose{3/2}$, which is incorrect. The answer key provided is $1 +$${n}\choose{2}$$+$${n}\choose{4}$. How can we get to this answer? And, how is my method faulty?

Assuming there are n points on a circle, then there are $C_n^2$ chords. If any three chords don't intersect in circle. How to show the circle will be divided into $1+ C_n^2 + C_n^4$ domains? Picture below is a example of 5 points on circle.

I was given the following task Define a bijection between ${(A^B)}^C$ and $A^{B \times C}$ I have no clue where to start and I don't understand the task. Could you please explain what I am required to show and how should I start the proof ?

One of the basic (and frequently used) properties of cardinal exponentiation is that $(a^b)^c=a^{bc}$. What is the proof of this fact? As Arturo pointed out in his comment, in computer science this is called .