meetforever/GRPO_CL huggingface dataset:
user: 已知 a 、 b 、 c 分别为 $\triangle A B C$ 的三个内角 A 、 B 、 C 的对边长， $a=2$ ，且 $(b+2) \sin \frac{C}{2} \cdot \sin \frac{A-B}{2}=c \cos \frac{A}{2} \cdot \cos \frac{B-C}{2}$. 若 D 是 B C 的中点,求 A D 长的最小值。原始答案为 $\frac{\sqrt{m}}{n}$ 的格式，请给出 $m + n$ 的值。
Answer: 6
user: 已知复数 $z$ 满足 $|z|=1$, 则 $\left|z^{3}+z^{2}-5 z+3\right|$ 的最大值为 ? 原始答案为 $\frac{m\sqrt{3}}{n}$ 的格式，请给出 $m + n$ 的值。
Answer: 155
user: 设 $x_{1}=3, x_{n+1}=\sqrt{x_{n}+14}-\sqrt{x_{n}+2}\left(n \in N^{*}\right)$, 求当$n=100$时$\left[x_{1}+x_{2}+\cdots+x_{n}\right]$ 的值。
Answer: 200
user: Find all positive integers that are within $250$ of exactly $15$ perfect squares. Please provide the sum of the endpoints of the intervals that contain these integers.
Answer: 1002
user: For which real numbers $c$ is there a straight line that intersects the curve  
$$  
y=x^{4}+9 x^{3}+c x^{2}+9 x+4  
$$  
in four distinct points? The original answer is in the format $c < \frac{m}{n}$. Please provide the value of $m + n$.
Answer: 251
user: Let $I_{m} = \int_{0}^{2 \pi} \cos (x) \cos (2 x) \cdots \cos (m x) d x$. For which integers $m, 1 \leqslant m \leqslant 10$, is $I_{m} \neq 0$? Please provide the sum of all such integers $m$.
Answer: 22
user: Define a polynomial $f_{n}(x)$, where $n \geqslant 0$ is $f_{0}(x)=1$, $n \geqslant 1$ is $f_{n}(0)=0$, and $n \geqslant 0$ is
$$
\frac{d}{d x}\left(f_{n+1}(x)\right)=(n+1) f_{n}(x+1)
$$
. Clearly decompose $f_{100}(1)$ into powers of different prime numbers, $a^{b}$, and find the value of $a+b$.
Answer: 200
user: Let $C$ be the unit circle $x^{2}+y^{2}=1$. A point $p$ is chosen randomly on the circumference $C$ and another point $q$ is chosen randomly from the interior of $C$ (these points are chosen independently and uniformly over their domains). Let $R$ be the rectangle with sides parallel to the $x$-and $y$-axes with diagonal $p q$. What is the probability that no point of $R$ lies outside of $C$? The original answer is in $\frac{n}{\pi^m}$format, please give the value of $m + n$.
Answer: 6
user: Evaluate $\int_{0}^{\infty} t^{-1 / 2} e^{-1985\left(t+t^{-1}\right)} d t$. You may assume that $\int_{-\infty}^{\infty} e^{-x^{2}} d x=\sqrt{\pi}$. The original answer is in the form $\frac{\sqrt{\pi}}{\sqrt{m}} e^{-2 \times m}$ . Please provide the value of $m + 1$.
Answer: 1986
user: Given positive integers $m$ and $n \geq m$, determine the largest number of dominoes ( $1 \times 2$ or $2 \times 1$ rectangles) that can be placed on a rectangular board with $m$ rows and $2 n$ columns consisting of cells ( $1 \times 1$ squares) so that:  
$\mathrm{(i)}$ each domino covers exactly two adjacent cells of the board;  
$\mathrm{(ii)}$ no two dominoes overlap;  
$\mathrm{(iii)}$no two form a $2 \times 2$ square; and  
$\mathrm{(iv)}$the bottom row of the board is completely covered by $n$ dominoes.
Please calculate the number of dominoes when $m = 6$ and $n = 5$
Answer: 27
user: Find (in closed form) the difference between the number of positive integers at most $2^{2017}$ with even weight and the number of positive integers at most $2^{2017}$ with odd weight. The original answer is in the format $2^m$. Please provide the value of m + 1.
Answer: 1010
user: Let $n$ be an integer greater than 1, and let $X$ be a set of $n$ elements. If the union $A_{1} \cup \cdots \cup A_{k}$ is a proper subset of $X$, and no element of $X$ is in exactly one of $A_{i}$, then the set of non-empty subsets $A_{1}, \ldots, A_{k}$ of $X$ is compact. Find the maximum cardinality of the set of proper non-empty subsets of $X$ such that no non-empty subset is compact, and compute its value for $n=100$.
Answer: 198
user: Fix an integer $n \geq 2$. An $n \times n$ sieve is an $n \times n$ array with $n$ cells removed so that exactly one cell is removed from each row and column. For any positive integer $k$, a stick is a $1 \times k$ or $k \times 1$ array. For any sieve $A$, let $m(A)$ denote the minimum number of sticks required to partition $A$. Find all possible values of $m(A)$, since $A$ is different in all possible $n \times n$ sieves, for $n=100$.
Answer: 198
user: Let $\mathbb{N}$ denote the set of all positive integers. Find a specific function $f: \mathbb{N} \rightarrow \mathbb{N}$ such that for $x = 1$ and $y = 1$, the expression $x^{2}-y^{2}+2 y(f(x)+f(y))$ becomes a square of an integer. Provide the value of $f(8)$.
Answer: 8
user: Find all pairs of positive real numbers $(x, y)$ such that $x y$ is an integer and
$$
x+y=\left\lfloor x^{2}-y^{2}\right\rfloor.
$$
Calculate the value of $x$ when $y=100$.
Answer: 101
user: Find all positive integers $a, b, n$ and prime numbers $p$ that satisfy the following conditions
$$
a^{2013}+b^{2013}=p^{n}
$$
Calculate the value of $n$ when $a=2$.
Answer: 2014
user: Olja writes down $n$ positive integers $a_{1}, a_{2}, \ldots, a_{n}$ smaller than $p_{n}$ where $p_{n}$ denotes the $n$-th prime number. Oleg can choose two (not necessarily different) numbers $x$ and $y$ and replace one of them with their product $x y$. If there are two equal numbers Oleg wins. Can Oleg guarantee a win? Please provide the smallest integer n for which Oleg can guarantee a win.
Answer: 2
user: Let $n$ be a positive integer. Let $B_{n}$ be the set of all binary strings of length $n$. For a binary string $s_{1} s_{2} \ldots s_{n}$, we define its twist in the following way. First, we count how many blocks of consecutive digits it has. Denote this number by $b$. Then, we replace $s_{b}$ with $1-s_{b}$. A string $a$ is said to be a descendant of $b$ if $a$ can be obtained from $b$ through a finite number of twists. A subset of $B_{n}$ is called divided if no two of its members have a common descendant. Find the largest possible cardinality of a divided subset of $B_{n}$. Please provide the value when $n = 4$. The answer should be an integer.
Answer: 4
user: We are given a combination lock consisting of 6 rotating discs. Each disc consists of digits $0,1,2, \ldots, 9$, in that order (after digit 9 comes 0 ). Lock is opened by exactly one combination. A move consists of turning one of the discs one digit in any direction and the lock opens instantly if the current combination is correct. Discs are initially put in the position 000000, and we know that this combination is not correct.  What is the least number of moves necessary to ensure that we have found the correct combination?
Answer: 999998
user: We call a sequence of $n$ digits one or zero a code. Subsequence of a code is a palindrome if it is the same after we reverse the order of its digits. A palindrome is called nice if its digits occur consecutively in the code. (Code (1101) contains 10 palindromes, of which 6 are nice.)  
What is the least number of palindromes in a code when $n=3$?
Answer: 4
user: Find all pairs $(x, y)$ of integers that satisfy the equation $$ x^{2} y+y^{2}=x^{3}. $$ Please provide the value of x + y for the pair that satisfies the equation.
Answer: -12
user: A friendly football match lasts 90 minutes. In this problem, we consider one of the teams, coached by Sir Alex, which plays with 11 players at all times.\na) Sir Alex wants for each of his players to play the same integer number of minutes, but each player has to play less than 60 minutes in total. What is the minimum number of players required?\nb) For the number of players found in a), what is the minimum number of substitutions required, so that each player plays the same number of minutes?\nRemark: Substitutions can only take place after a positive integer number of minutes, and players who have come off earlier can return to the game as many times as needed. There is no limit to the number of substitutions allowed.\nPlease provide the sum of the answers for parts a) and b).
Answer: 35
user: Find all polynomials $P$ with integer coefficients such that $P(0) \neq 0$ and  
$$  
P^{n}(m) \cdot P^{m}(n)  
$$  
is a square of an integer for all nonnegative integers $n, m$. 
Remark : For a nonnegative integer $k$ and an integer $n$, $P^k(n)$ is defined as follows: $P^k(n) = n\text{ if }k = 0$ and $P^k(n)=P(P^{k-1}(n))$ if $k>0.$
Please provide the sum of the coefficients of the polynomial.
Answer: 2
user: 已知矩阵
$$
A=\left[\begin{array}{ccc}
2 & 0 & 0 \\
1 & 3 & 1 \\
-1 & 1 & 3
\end{array}\right], A^{10}=\left[\begin{array}{lll}
b_{11} & b_{12} & b_{13} \\
b_{21} & b_{22} & b_{23} \\
b_{31} & b_{32} & b_{33}
\end{array}\right] \text {, 求 } b_{22}.
$$
Answer: 524800
user: 正三棱雉 $P-A B C$ 中, $A B=1, A P=2$, 过 $A B$ 的平面 $\alpha$ 将其体积平分, 则棱 $P C$与平面 $\alpha$ 所成角的余弦值为。原始答案的形式为\frac{m\sqrt{n}}{k}，请给出m + n + k的值。
Answer: 18
user: 设 $f(x)=\frac{1}{x^{3}-x}$, 求满足不等式 $f(2)+f(3)+\cdots+f(n)>\frac{499}{2020}$ 的最小正整数 $n$. 请给出$n$的值。
Answer: 13
user: A positive integer $k \geqslant 3$ is called fibby if there exists a positive integer $n$ and positive integers $d_{1}<d_{2}<\ldots<d_{k}$ with the following properties:  - $d_{j+2}=d_{j+1}+d_{j}$ for every $j$ satisfying $1 \leqslant j \leqslant k-2$,  - $d_{1}, d_{2}, \ldots, d_{k}$ are divisors of $n$,  - any other divisor of $n$ is either less than $d_{1}$ or greater than $d_{k}$.  Find the largest fibby number.
Answer: 4
user: 设 $A$ 为三元集合（三个不同实数组成的集合），集合 $B=\{x+y \mid x, y \in A, x \neq y\}$ ，若 $B=$ $\left\{\log _{2} 6, \log _{2} 10, \log _{2} 15\right\}$ ，则集合 $A=$ $\qquad$.若集合\A={a,\log_b,\log_c\},其中$a,b,c$为正整数，求$a+b+c$.
Answer: 49
user: 已知函数 $f(x)=(\sqrt{1+x}+\sqrt{1-x}-3)\left(\sqrt{1-x^{2}}+1\right)$ 的最小值为 $m$, 最大值为 $M$, 则 $\frac{M}{m}$ 的原始答案为 $\frac{a-b\sqrt{c}}{d} $的形式。请给出 $a + b + c + d$ 的值。
Answer: 8
user: 已知向量 $\boldsymbol{a}, \boldsymbol{b}, \boldsymbol{c}$ 满足 $|\boldsymbol{a}|:|\boldsymbol{b}|:|\boldsymbol{c}|=1: k: 3\left(k \in \mathbf{Z}_{+}\right)$, 且 $\boldsymbol{b}-\boldsymbol{a}=2(\boldsymbol{c}-\boldsymbol{b})$, 若 $\alpha$ 为 $\boldsymbol{a}, \boldsymbol{c}$ 的夹角，则原始答案为$-\frac{m}{n}$格式，请给出$m + n$的值。
Answer: 13
user: 已知正四面体可容纳 10 个半径为 1 的小球，则正四面体棱长的最小值为？答案的格式为$a+b\sqrt{c}$，请给出$a+b+c$的值。
Answer: 12
user: 已知 $\triangle A B C$ 为椭圆 $\frac{x^{2}}{9}+\frac{y^{2}}{4}=1$ 的内接三角形，且 $A B$ 过点 $P(1,0)$ ，则 $\triangle A B C$ 的面积的最大值为 ? 请给出最大值的答案格式为 $\frac{m\sqrt{n}}{k} $的格式，请计算 $m + n+k$ 的值。
Answer: 21
user: 已知过点 $P(3,0)$ 斜率为 $k$ 的直线 $l$ 交双曲线 $C: x^{2}-\frac{y^{2}}{3}=1$ 右支于 $A, B$ 两点, $F$ 为双曲线 $C$ 的右焦点, 且 $|A F|+|B F|=16$, 求 $k$ 的值。请给出所有满足条件的|k|的和。
Answer: 6
user: 设实数 $t \in[0, \pi]$ 。若关于 $x$ 的方程 $\cos (x+t)=1-\cos x$ 有解，求 $t$ 的取值范围中包含几个整数？
Answer: 3
user: 设自然数 $n \geqslant 3$, 实数 $x_{1}, x_{2}, \cdots, x_{n}$ 满足 $x_{1}+x_{2}+\cdots+x_{n}=n, x_{1}^{2}+x_{2}^{2}+\cdots+x_{n}^{2}=n^{2}$, 求 $\sum_{i=1}^{n} x_{i}^{3}$ 的最小值 。请提供n=3时最小值的整数结果。
Answer: 23
user: 已知 $f(x)=2 m x^{2}-2 m x-8 x+9, g(x)=m x-m$ ，对任意 $x \in \mathbf{R}, f(x)$ 与 $g(x)$ 至少有一个为正数，则实数 m 的取值范围是. 请给出该区间的两个端点之和.
Answer: 8
user: 过抛物线 $E: y^{2}=2 x$ 的焦点 F 作两条斜率之积为 $-\frac{1}{2}$ 的直线 $l_{1}, l_{2}$, 其中 $l_{1}$ 交 $E$ 于 $A, C$ 两点, $l_{2}$ 交 E 于 $B, D$ 两点, 求$|A C|+3|B D|$ 最小值中实部加虚部的值。
Answer: 0
user: 设正三棱雉 $P-A B C$ 的底面边长为 1, 高为 $\sqrt{2}$, 过底边 $B C$ 作此三棱雉的截面，则截面面积的最小值为. 原始答案为\frac{m\sqrt{n}}{k}的形式，请给出m + n + k的值。
Answer: 45
user: 已知点 H 为 $\triangle A B C$ 的垂心，且满足 $\overrightarrow{H A}+2 \overrightarrow{H B}+6 \overrightarrow{H C}=0$ ，则角 $B=$ 的原始答案为 \frac{m\pi}{n}，请给出 m + n 的值。
Answer: 4
user: 数列 $\left\{a_{n}\right\}$ 的相邻两项 $a_{n}$ 和 $a_{n+1}$ 为二次方程 $x^{2}-3 n x+c_{n}=0(n=1,2,3, \cdots)$的两个根，当 $a_{1}=1$ 时，求 $c_{n}$ 。写出$n=4$时$c_n$的值。
Answer: 143
user: 设函数 $f(x)$ 为奇函数, 当 $x \geqslant 0$ 时, $f(x)=x^{2}$ 。则不等式 $$ f(f(x))+f(x-1)<0 $$ 的解集的上限为一个涉及 \sqrt{} 的表达式，请给出该表达式的整数近似值。
Answer: 1
user: 已知复数 $z_{1} 、 z_{2}$ 满足: $$ \begin{aligned} & \left|z_{1}\right|=\left|z_{1}-2 z_{2}\right|, z_{1} \overline{z_{2}}=\sqrt{3}(1-\mathrm{i}). \\ & \text { 则 } \frac{z_{1}}{z_{2}}= \end{aligned} $$ 请给出 $\frac{z_{1}}{z_{2}}$ 的实部和虚部的和。
Answer: 2
user: 设正三棱雉 $P-A B C$ 的底面边长为 1 、高为 $\sqrt{2}$ ，过底边 $B C$ 作此三棱雉的截面。则截面面积的最小值为多少？原始答案为$\frac{m\sqrt{n}}{k}$的形式，请给出$m + n + k$的值。
Answer: 45
user: 已知 H 为 $\triangle A B C$ 的垂心，且满足
$\overrightarrow{H A}+2 \overrightarrow{H B}+6 \overrightarrow{H C}=0$ 。
则 $\frac{3}{\pi}\angle B=$ $\qquad$.
Answer: 1
user: 设 $G(V, E)$ 是连通的简单图. 称 $E$ 的子集 $H$ 为 $G$ 的"偶度子图"，如果对任何 $x \in V, H$ 中共有偶数条边以 $x$ 为顶点. 设 $|V|=v,|E|=e$ ，问： $G$ 有多少个"偶度子图"？请提供v = 3时的答案。
Answer: 1
user: 给定奇素数 $p$ 和整数 $a$. 若$p\equiv-1(mod4)$，且$p|a$时，求方程 $x^{2}+y^{2} \equiv a(\bmod p)$ 在模 $p$ 意义下的解的个数。
Answer: 1
user: For all positive integers $n, k$, let $f(n, 2 k)$ be the number of ways an $n \times 2 k$ board can be fully covered by $n k$ dominoes of size $2 \times 1$. (For example, $f(2,2)=2$ and $f(3,2)=3$.) Find all positive integers $n$ such that for every positive integer $k$, the number $f(n, 2 k)$ is odd. Please provide the value of f(n, 2 k) when k = 1. The answer should be in the format 2^k-1, directly give the value of m + n.
Answer: 0
user: The numbers $p$ and $q$ are prime and satisfy  $$\frac{p}{p+1}+\frac{q+1}{q}=\frac{2 n}{n+2}$$  for some positive integer $n$. Please provide the sum of all possible values of $q-p$.
Answer: 10
user: Let $k$ be a positive integer. Lexi has a dictionary $\mathcal{D}$ consisting of some $k$-letter strings containing only the letters $A$ and $B$. Lexi would like to write either the letter $A$ or the letter $B$ in each cell of a $k \times k$ grid so that each column contains a string from $\mathcal{D}$ when read from top-to-bottom and each row contains a string from $\mathcal{D}$ when read from left-to-right. What is the smallest integer $m$ such that if $\mathcal{D}$ contains at least $m$ different strings, then Lexi can fill her grid in this manner, no matter what strings are in $\mathcal{D}$? Please provide the value of m when k = 2.
Answer: 2
user: For a sequence $a_{1}<a_{2}<\cdots<a_{n}$ of integers, a pair ( $a_{i}, a_{j}$ ) with $1 \leq i<$ $j \leq n$ is called \underline{interesting} if there exists a pair ( $a_{k}, a_{l}$ ) of integers with $1 \leq k<l \leq n$ such that  
$$\frac{a_{l}-a_{k}}{a_{j}-a_{i}}=2$$  
For each $n \geq 3$, find the largest possible number of interesting pairs in a sequence of length $n$. Please provide the value of this expression when $n = 5$.
Answer: 7
user: Find the largest positive integer \(d\) for which there exists a degree $d$ polynomial $P$ with real coefficients such that there are at most $d$ different values among $P(0), P(1), \ldots, P\left(d^{2}-\right.$ $d)$.
Answer: 3
user: Determine all integers $m$ for which the $m \times m$ square can be dissected into five rectangles, the side lengths of which are the integers $1,2,3, \ldots, 10$ in some order. Please provide the sum of all possible values of $m$.
Answer: 24
user: Determine all real constants $t$ such that whenever $a, b, c$ are the lengths of the sides of a triangle, then so are $a^{2}+b c t, b^{2}+c a t, c^{2}+a b t$.If the length of the interval in which \(t\) lies is \(\frac{a}{b}\), find \(a + b\).
Answer: 7
user: A domino is a $2 \times 1$ or $1 \times 2$ tile. Determine in how many ways exactly $n^{2}$ dominoes can be placed without overlapping on a $2 n \times 2 n$ chessboard so that every $2 \times 2$ square contains at least two uncovered unit squares which lie in the same row or column. Please provide the value when n = 1.
Answer: 4
user: Let $m$ be a positive integer. Consider a $4 m \times 4 m$ array of square unit cells. Two different cells are related to each other if they are in either the same row or in the same column. No cell is related to itself. Some cells are coloured blue, such that every cell is related to at least two blue cells. Determine the minimum number of blue cells. Please provide the answer when $m=1$.
Answer: 6
user: The $n$ contestants of an EGMO are named $C_{1}, \ldots, C_{n}$. After the competition they queue in front of the restaurant according to the following rules.  
- The Jury chooses the initial order of the contestants in the queue.  
- Every minute, the Jury chooses an integer $i$ with $1 \leq i \leq n$.  
- If contestant $C_{i}$ has at least $i$ other contestants in front of her, she pays one euro to the Jury and moves forward in the queue by exactly $i$ positions.  
- If contestant $C_{i}$ has fewer than $i$ other contestants in front of her, the restaurant opens and the process ends.  
Determine for every $n$ the maximum number of euros that the Jury can collect by cunningly choosing the initial order and the sequence of moves.
Please provide the value when n = 9.
Answer: 502
user: Determine whether for every real number $t$ such that $0<t<\frac{1}{2}$ there exists an infinite set $S$ of positive integers such that  
$$  
|x-m y|>t y  
$$  
for every pair of different elements $x$ and $y$ of $S$ and every positive integer $m$ (i.e. $m>0$ ).The original answer is in the form of $t<\left\{\frac{s_{n-1}}{s_{n}}\right\}<\frac{a}{b}$. Find the value of $a+b$.
Answer: 3
user: Let $n$ be a positive integer. Dominoes are placed on a $2 n \times 2 n$ board in such a way that every cell of the board is adjacent to exactly one cell covered by a domino. For each $n$, determine the largest number of dominoes that can be placed in this way. (A domino is a tile of size $2 \times 1$ or $1 \times 2$. Dominoes are placed on the board in such a way that each domino covers exactly two cells of the board, and dominoes do not overlap. Two cells are said to be adjacent if they are different and share a common side.) Please provide the largest number of dominoes when n = 6.
Answer: 21
user: Let $n$ be a positive integer and fix $2 n$ distinct points on a circumference. Split these points into $n$ pairs and join the points in each pair by an arrow (i.e., an oriented line segment). The resulting configuration is good if no two arrows cross, and there are no arrows $\overrightarrow{A B}$ and $\overrightarrow{C D}$ such that $A B C D$ is a convex quadrangle oriented clockwise. Determine when n=6， the number of good configurations.
Answer: 924
user: 设 $O$ 为 $\triangle A B C$ 的外心, 且满足 $\overrightarrow{O A}+\overrightarrow{O B}=\overrightarrow{O C}.$  则 $\frac{3}{\pi}\angle A C B=
Answer: 2
user: 设 $f(x), g(x)$ 分别是定义在 $\mathbf{R}$ 上的奇函数和偶函数, 且 $f(x)+g(x)=2^{x}$. 若对 $x \in[1,2]$, 不
等式 $a f(x)+g(2 x) \geqslant 0$ 恒成立, 则实数 $a$ 的最小值的$6$是多少 $\qquad$.
Answer: -17
user: 设 $x, y$ 均为非零实数, 且满足 $\frac{x \sin \frac{\pi}{5}+y \cos \frac{\pi}{5}}{x \cos \frac{\pi}{5}-y \sin \frac{\pi}{5}}=\tan \frac{9 \pi}{20}$.   求 $\frac{y}{x}$ 的值;
Answer: 1
user: 袋中装有 2 个红球、 3 个白球、 4 个黄球，从中任取 4 个球，则其中三种颜色的球都有的概率的7倍是 $\qquad$.
Answer: 4
user: 已知函数 $f(x)=-x^{3}+a x^{2}+b x+c(a, b, c \in \mathbf{R})$ 在 $(-\infty, 0)$ 上单调递减, 在 $(0,1)$ 上单调递增,且 $f(x)$ 在 $\mathbf{R}$ 上有三个零点, 1 是其中的一个零点.求 $f(2)$ 最小值的 $2 $倍是多少
Answer: -5
user: 已知 $a$ 为常数, 函数
$f(x)=\ln \frac{1-x}{1+x}-a x$.
 若 $a=-\frac{8}{3}$, 求 $f(x)$ 的取极大值时的x值的2倍为多少.
Answer: 1
user: 已知对一切的 $x \in \mathbf{R}$ 恒有  $3 \sin ^{2} x-\cos ^{2} x+4 a \cos x+a^{2} \leqslant 31$. 求实数 $a$ 的取值范围. 请给出区间的端点和.
Answer: 0
user: 设等比数列 $\left\{a_{n}\right\}$ 的前 $n$ 项和为 $S_{n}, S_{n}=2^{n}+r$ ( $r$ 为常数),记 $b_{n}=2\left(1+\log _{2} a_{n}\right)\left(n \in \mathbf{N}^{*}\right)$.若对于任意的正整数 $n$, 都有 $\frac{1+b_{1}}{b_{1}} \cdot \frac{1+b_{2}}{b_{2}} \cdots \frac{1+b_{n}}{b_{n}} \geqslant k \sqrt{n+1}$ 成立, 求实数 $k$ 的最大值的$2\sqrt{2}$倍是多少.
Answer: 3
user: 在三棱锥 $P-A B C$ 中, 三条棱 $P A$ 、 $P B 、 P C$ 两两垂直，且 $P A=1, P B=P C=2$. 若 $Q$ 为三棱锥 $P-A B C$ 外接球的球面上任一点, 则 $Q$ 到面 $A B C$ 距离的最大值减去$\frac{\sqrt{6}}6$的结果的2倍为 $\qquad$.
Answer: 3
user: 在 $\triangle A B C$ 中, $\cos B=\frac{1}{4}$. 则 $\frac{1}{\tan A}+\frac{1}{\tan C}$的最小值的$\frac{\sqrt{15}}3$倍为 $\qquad$.
Answer: 2
user: Let $a_{1}, a_{2} \ldots, a_{51}$ be non-zero elements of a field. We simultaneously replace each element with the sum of the 50 remaining ones. In this way we get a sequence $b_{1} \ldots, b_{51}$. If this new sequence is a permutation of the original one, what can be the characteristic of the field? Please provide the sum of the possible characteristics.
Answer: 9
user: Let $A$ be a real $4 \times 2$ matrix and $B$ be a real $2 \times 4$ matrix such that $$ AB=\left(\begin{array}{cccc} 1 & 0 & -1 & 0 \\ 0 & 1 & 0 & -1 \\ -1 & 0 & 1 & 0 \\ 0 & -1 & 0 & 1 \end{array}\right) $$ Find $B A.$ Provide the sum of all elements in the resulting matrix.
Answer: 4
user: How many nonzero coefficients can a polynomial $P(z)$ have if its coefficients are integers and $|P(z)| \leq 2$ for any complex number $z$ of unit length? Please provide the sum of all possible numbers of nonzero coefficients.
Answer: 3
user: For each positive integer $k$, find the smallest number $n_{k}$ for which there exist real $n_{k} \times n_{k}$ matrices $A_{1}, A_{2}, \ldots, A_{k}$ such that all of the following conditions hold:  
(1) $A_{1}^{2}=A_{2}^{2}=\ldots=A_{k}^{2}=0$,  
(2) $A_{i} A_{j}=A_{j} A_{i}$ for all $1 \leq i, j \leq k$, and  
(3) $A_{1} A_{2} \ldots A_{k} \neq 0$.  
Please provide the sum of the smallest $n_k$ values for $k = 2$ and $k = 3$.
Answer: 12
user: Compute the sum of the series \( \sum_{k=0}^{\infty} \frac{1}{(4 k+1)(4 k+2)(4 k+3)(4 k+4)}=\frac{1}{1 \cdot 2 \cdot 3 \cdot 4}+\frac{1}{5 \cdot 6 \cdot 7 \cdot 8}+\cdots  \). The original answer is in a special format：$\frac{\ln m}n-\frac\pi{p}.$ provide the sum of the denominators in the expression.
Answer: 30
user: (a) A sequence $x_{1}, x_{2}, \ldots$ of real numbers satisfies $$ x_{n+1}=x_{n} \cos x_{n} \quad \text { for all } \quad n \geq 1 $$ Determine if this sequence converges for all initial values $x_{1}$. (b) A sequence $y_{1}, y_{2}, \ldots$ of real numbers satisfies $$ y_{n+1}=y_{n} \sin y_{n} \quad \text { for all } \quad n \geq 1 $$ Determine if this sequence converges for all initial values $y_{1}$. If the answer to (a) is NO and (b) is YES, provide the sum of their binary representations as a single integer.
Answer: 1
user: Given an integer $n>1$, let $S_{n}$ be the group of permutations of the numbers $1,2, \\ldots, n$. Two players, A and B, play the following game. Taking turns, they select elements (one element at a time) from the group $S_{n}$. It is forbidden to select an element that has already been selected. The game ends when the selected elements generate the whole group $S_{n}$. The player who made the last move loses the game. The first move is made by A. For which values of n does player A have a winning strategy? Please provide the sum of these values of n.
Answer: 5
user: Consider the following sequence \(\left(a_{n}\right)_{n=1}^{\infty}=(1,1,2,1,2,3,1,2,3,4,1,2,3,4,5,1, \ldots)\). Find all pairs \((\alpha, \beta)\) of positive real numbers such that \(\lim \limits_{n \rightarrow \infty} \frac{\sum\limits_{k=1}^{n} a_{k}}{n^{\alpha}}=\beta\). The original answer is in \(\frac{\sqrt{m}}{n}\) format, please give the value of \(m + n\).
Answer: 5
user: We say that a subset of $\mathbb{R}^{n}$ is $k$-almost contained by a hyperplane if there are less than $k$ points in that set which do not belong to the hyperplane. We call a finite set of points $k$-generic if there is no hyperplane that $k$-almost contains the set. For each pair of positive integers $k$ and $n$, find the minimal number $d(k, n)$ such that every finite $k$-generic set in $\mathbb{R}^{n}$ contains a $k$-generic subset with at most $d(k, n)$ elements. Calculate the value of $d(k, n)$ when $k = 2$ and $n = 2$, and provide the result of k + n + d(k, n).
Answer: 8
user: Let $F(0)=0, F(1)=\frac{3}{2}$, and $F(n)=\frac{5}{2} F(n-1)-F(n-2)$ for $n \geq 2$. Determine whether or not $\sum\limits_{n=0}^{\infty} \frac{1}{F\left(2^{n}\right)}$ is a rational number. Please provide the integer value of the sum.
Answer: 1
user: An $n \times n$ complex matrix $A$ is called $t$-normal if $A A^{t}=A^{t} A$ where $A^{t}$ is the transpose of $A$. For each $n$, determine the maximum dimension of a linear space of complex $n \times n$ matrices consisting of t-normal matrices. Please provide the value of the dimension when n = 11. The answer should be in the format \frac{m}{n}, directly give the value of m + n.
Answer: 134
user: Determine all complex numbers $\lambda$ for which there exist a positive integer $n$ and a real $n \times n$ matrix $A$ such that $A^{2}=A^{T}$ and $\lambda$ is an eigenvalue of $A$. The answer is $\frac{m \pm \sqrt{n} i}{p}$ ,please give the sum of m,n and p.
Answer: 4
user: Determine all rational numbers $a$ for which the matrix
$$
\left(\begin{array}{cccc}
a & -a & -1 & 0 \\
a & -a & 0 & -1 \\
1 & 0 & a & -a \\
0 & 1 & a & -a
\end{array}\right)
$$
is the square of a matrix with all rational entries. Provide the integer value of $a$ that satisfies the condition.
Answer: 0