HDTenEightyP/NetNews huggingface dataset:
From: hibrown@vidar.albany.edu (Herb Brown)
Subject: Re: A problem with Maple integration ..
Organization: State University of New York at Albany
Distribution: sci
Date: Mon, 14 Sep 92 14:50:08 GMT

In article <1992Sep13.125316.7423@sarah.albany.edu> hibrown@thor.albany.edu (Herb Brown) writes:
>In article <1992Sep12.160849.14864@vax5.cit.cornell.edu> fnvy@vax5.cit.cornell.edu writes:
>>Possible Maple error in integration
>>
>>This is what I did with xmaple (Maple V) on a sparc station:
>>
>>> f:=sqrt((1+s)/(1-s));
>>                                            1/2
>>                                     (1 + s)
>>                                f := ----------
>>                                            1/2
>>                                     (1 - s)
>>
>>_____________________________________________________________________________
>>> int(f*s,s=-1..1,continuous);
>>                                    - 1/2 Pi
>>
>>Whereas the correct answer should be 
>>
>>               Pi/2
>>
>>Did I do something wrong?  Or, is this a bug on the current version Maple?
>>All discussion or advice are welcome.  Many thanks for your attention.
>>
>>Wei-Yan
>>
>
>Perhaps the following may help understand what Maple is attempting to do:
>
>
>> F := int( x*sqrt((1 + x)/(1 - x)), x);
>
>                               2 1/2                         2 1/2
>              F := 1/2 x (1 - x )    - 1/2 arcsin(x) + (1 - x )
>
>> subs( x = 1, F) - subs( x = -1, F);
>
>                    ans := - 1/2 arcsin(1) + 1/2 arcsin(-1)
>
>> simplify(");
>                                    - 1/2 Pi
>
>
>Herb
>
>-- 

What I neglected to point out was that Maple does not correctly integrate the
function  x*sqrt((1 + x)/(1 - x)).

However, it is a curious phenomenon that Maple computes the correct integral
of  x*sqrt((1 + x)^2/(1 - x^2)) ,  which is the original function with the
denominator rationalized!!!

Herb


-- 
---------------------------------------------------------------------------
Herb Brown  Math Dept  The Univ at Albany  Albany, NY 12222  (518) 442-4640
Director,                                          hibrown@math.albany.edu  
Computer Assisted Instruction in Mathematics       hibrown@thor.albany.edu
Newsgroups: sci.math.symbolic
From: dmm0t@rincewind.mech.Virginia.EDU (David Meyer)
Subject: Transforming DE's with Mathematica 2.0 (or 2.1)
Organization: University of Virginia
Date: Wed, 9 Sep 1992 17:21:39 GMT

How do you perform a variable transformation on a PDE?  For instance,
I have something like Laplacian[phi[x,y]], and I want to do the
transformation (x,y) -> (xi,eta), where xi=x and eta=y/f(x).  Is there
a way to do this?  I've used macsyma to do this in the past, but it's
a real pain copying equations from one to the other.

On a much more general note, is there a FAQ for this newsgroup, and if
so, where?

		Thanks,
			Dave
-- 
David M. Meyer                             Mechanical & Aerospace Engineering
dmm0t@virginia.edu                         University of Virginia
dmm0t@rincewind.mech.Virginia.EDU (NeXTmail)
From: martin@math.rwth-aachen.de (  Martin Schoenert)
Newsgroups: sci.math.symbolic
Subject: Re: Group theory on the Mac/Quadra
Keywords: group non-commutative algebra quadra
Date: 10 Sep 92 13:30:55 GMT
Organization: Rechnerbetrieb Informatik  /  RWTH Aachen

In his article of 6-Sep-92 Ulf Wostner (wostner@nes.nersc.gov) writes:

    I would like to use Mathematica to work with groups and would
    greatly appreciate any pointers to existing work.

    Alternatively, is there a version of GAP that runs on the Quadra?

    Thanks,

    Ulf Wostner

Steve Linton  (sl52@cus.cam.ac.uk)  forwarded this  request  to  the  GAP
forum, where Joachim Neubueser (neubuese@math.rwth-aachen.de) answered:

    Steve Linton  has  forwarded a  question  of  Ulf  Wostner  about  the
    availability  of GAP on  the Quadra.  We have also been asked  several
    times about the availability on other members of the Macintosh family.
    I therefore want to answer in the gap-forum:

    We do not have any  Macs at  Lehrstuhl D in Aachen and we also have no
    easy access to such machines. Therefore in view of our restrictions in
    manpower we do not plan to engulf ourselves  into a portation to these
    computers.  On  the  other  hand  we  fully  realize  that  these  are
    widespread  machines, perhaps even more so  in the US than in  Germany
    and we would like to see GAP being  available on them.   Therefore the
    public challenge if there is  somebody  who is  willing  to  do such a
    port. We  would certainly  be  willing to be of any possible help with
    this, in particular to provide any information or explanation  needed.
    In case somebody volunteers, would (s)he please contact us or announce
    this  plan in  the  gap-forum, just  in  order  to  avoid  unnecessary
    duplication of work.

    I would like to mention in  this context that the port to 386/486  PCs
    was done by Steve Linton, so also not in Aachen, and I like to express
    our thanks to him for this help.

    Hoping for (many) volunteers        Joachim Neubueser

To this N. Mendelsohn (mendel@ccu.umanitoba.ca) answered:

    GAP has been ported to Mac at the University of Manitoba.
    It will be put on our main frame within a week from  which it 
    will be obtainable using ftp anonymous.  I will send details as
    soon as possible.  N. S. Mendelsohn.

I will forward his details to this group  when  he sends them to  the GAP
forum.  I  cannot help with Ulf's first request, namely  group theory  in
Mathematica.  I know that there is a very basic package for  group theory
in  Maple.   If  someone  has something for  Mathematica I would  also be
interested to hear about it.

Kindly, Martin.

--
Martin Sch"onert,   Martin.Schoenert@Math.RWTH-Aachen.DE,  +49 241 804551
Lehrstuhl D f"ur Mathematik, Templergraben 64, RWTH, D 51 Aachen, Germany
Lines: 9
Date: Wed,  9 Sep 92 16:40:29 MDT
From: darrenp@bones.et.byu.edu (Darren Pulsipher)
Newsgroups: sci.math.symbolic
Distribution: world
Organization: Brigham Young University, Provo UT USA
Subject: MathLink Questions for Mathematica



I would like to know if there is any information on MathLink C functions.
I have looked at the header files and the information given in Wolframs book,
but I am still confused on the form of the functions and exactly how it works.
If any has any suggestion please send me E-mail.


					Darren Pulsipher
From: andre@ramsey.cs.laurentian.ca (Andre Roberge)
Subject: Help solving a non-linear ODE
Organization: Dept. of Computer Science, Laurentian University, Sudbury, ON
Date: Fri, 11 Sep 1992 17:55:09 GMT

Given y = y(x) and using y' to denote differentiation of y with respect
to x, I'd like to solve the equation

y'' = y^3 - a y + b/(y^3)

in closed form.  If that can help you (and I doubt it very much),
a more general problem to solve is

y'' = y^3 - a y + b/(y^3)  - c y/(d + y^2)

where a, b, c and d are positive constants.

------aside.... -----

So far I've been able to show that if I write z = y^2, I can rewrite
my original equation in the form

z'' = A + B z + C z^2

where A, B and C are not necessarily positive.  (Note that there is an
arbitrary constant hidden somewhere).  What really interested me in
this particular form of the equation is that I could find one closed
solution in closed form, namely

z = G [tanh (H x)]^2 + D.

Unfortunately it is not a solution of the original equation  (so that the
arbitrary constant of integration is not so arbitrary after all...:-(

--------------------

Regarding boundary conditions, you can assume either periodic boundary
conditions  (on the interval [-L, L]) whatever else suits you :-)

Any takers?

Please reply to  andre@gollum.phys.laurentian.ca

---  Andre

Andre Roberge
Physics Dept.
Laurentian University
Sudbury, Ontario, Canada.

Newsgroups: sci.math.symbolic
From: Richard J. Gaylord <gaylord@ux1.cso.uiuc.edu>
Subject: Re: commercial version of IBM's "new scratchpad"
X-Xxdate: Thu, 10 Sep 92 02:23:00 GMT
X-Useragent: Nuntius v1.1.1d9
Organization: University of Illinois
Date: Thu, 10 Sep 1992 07:21:34 GMT
X-Xxmessage-Id: <A6D46204D6019B12@mm-mac18.mse.uiuc.edu>

i've been speaking to the NAG people about running AXIOM 

 they tell me that it requires 32 Mb RAM, 100 Mb of disk space and 100 Mb
swap space.

i think that the swap space requirement may be an upper limit
recommentdation necessary only for graphics and such. i hope so as its
difficult to free up  200 Mb of space for this program. 

and i thought Mathematica was a machine hog.
Newsgroups: sci.math.symbolic
From: stiv@stat.rice.edu (david n stivers)
Subject: $200 student Mathematica?
Organization: Dept. of Statistics, Rice University
Distribution: usa
Date: Thu, 10 Sep 1992 14:23:12 GMT

What is the deal with cut-rate student versions? The university
store here sells it for $650 or so, but I thought that it was
available for much less than that.

What are the limitations (w/respect the full version)?
I understand that it doesn't have co-processor support; is there anything else 
lacking?

Any caveats to running it on an Apple PowerBook 145 8/40? (how 'bout 4/40?)

I'm mostly interested in the symbolic math and the notebook features,
with only occasional graphics usage.


Thanks,

David
-- 

david n stivers stiv@rice.edu
From: ara@zurich.ai.mit.edu (Allan Adler)
Newsgroups: sci.math.symbolic
Subject: Re: commercial version of IBM's "new scratchpad"
Date: 10 Sep 92 01:57:39 GMT
Distribution: sci.math.symbolic
Organization: M.I.T. Artificial Intelligence Lab.

Well, what resources of RAM and disk space does it require?
From: fnvy@vax5.cit.cornell.edu
Newsgroups: sci.math.symbolic
Subject: A problem with Maple integration ..
Date: 12 Sep 92 16:08:49 EDT
Distribution: sci
Organization: Cornell University

Possible Maple error in integration

This is what I did with xmaple (Maple V) on a sparc station:

    |\^/|      MAPLE V
._|\|   |/|_.  Copyright (c) 1981-1990 by the University of Waterloo.
 \  MAPLE  /   All rights reserved.  MAPLE is a registered trademark of
 <____ ____>   Waterloo Maple Software.
      |        Type ? for help.
> f:=sqrt((1+s)/(1-s));
                                            1/2
                                     (1 + s)
                                f := ----------
                                            1/2
                                     (1 - s)

_____________________________________________________________________________
> integrate(f*s,s,-1,1);
Error, (in int) invalid arguments
_____________________________________________________________________________
> int(f*s,s,-1,1);
Error, (in int) invalid arguments
_____________________________________________________________________________
> help(integrate);
_____________________________________________________________________________
> int(f*s,s=-1..1,continuous);
                                    - 1/2 Pi


Whereas the correct answer should be 

               Pi/2


Did I do something wrong?  Or, is this a bug on the current version Maple?
All discussion or advice are welcome.  Many thanks for your attention.

Wei-Yan
From: bardo@ief-paris-sud.fr (Bardo Muller)
Newsgroups: sci.math.symbolic
Subject: mma and maxwells equations
Keywords: mathematica Maxwell
Date: 10 Sep 92 13:03:56 GMT
Reply-To: bardo@ief-paris-sud.fr
Followup-To: sci.math.symbolic
Organization: Universite de Paris

Dear readers,

I'd like to do symbolic calulations on Maxwells equations
with mma's VectorAnalysis or another package. 
Please mail me your experience if such. The doc isn't very eloquent
on that and I get the message

Solve::tdep: The equations appear to involve transcendental functions of the
     variables in an essentially non-algebraic way.

Thanks

Bardo

___________________________________________________________________________
| Bardo MULLER                          | phone  : [33] [1] 69 41 78 50    |
| Institut d'Electronique Fondamentale  | fax    : [33] [1] 60 19 25 93    |
| Bat. 220 Universite Paris Sud         | e-mail : bardo@ief-paris-sud.fr  |
| 91405 ORSAY CEDEX FRANCE              |             THE NET WORKS !      |
|_______________________________________|__________________________________|
Newsgroups: sci.math.symbolic
From: ulrich@cs.tu-berlin.de (Ulrich Wittenberg)
Subject: Mathematica: A FIT Question
Organization: Technical University of Berlin, Germany
Distribution: sci
Date: Mon, 14 Sep 1992 15:00:09 GMT


Good morning, Ladies and Gentlemen.

Using mathematica I want to fit a set of points {xi, yi} to 1/x, 1/x^2
etc like this:

In[1] = data = {{-100, 0.03}, <<n>>, {200, 0.005}};

In[2] = fitted = Fit[data, {1, 1/x, 1/x^2},x]

But all i get is Indeterminate due to a division by zero.

Would you please be so kind and tell me what i'm doing wrong.

Thanks in advance
Ulrich
-- 
Ulrich Wittenberg, FG Computer Graphics, Institut fuer technische Informatik
Fachbereich 20 (Informatik), TU Berlin, Franklinstrasse 28/29, 
1000 Berlin 10, Germany, Europe, Terra, Sol, Milky Way, Universe (Backyard)
Newsgroups: sci.math.symbolic
From: Ray Zimmerman <Ray-Zimmerman@cornell.edu>
Subject: Re: Matlab. Compared to mma, mathcad?
X-Xxmessage-Id: <A6DA168DBD01E0B5@ziklag.ee.cornell.edu>
X-Xxdate: Mon, 14 Sep 92 15: 14:37 GMT
Nntp-Posting-User: rz10@cornell.edu
Organization: Electrical Engineering, Cornell University
X-Useragent: Nuntius v1.1.1d9
Date: Mon, 14 Sep 1992 14:09:31 GMT

In article <1992Sep14.023901.23508@ucsu.Colorado.EDU> David Knapp,
knapp@spot.Colorado.EDU writes:
>Can anyone fill my in on the pros and cons of matlab? I've used both 
>Mathematica and Mathcad for windows. Can any users compare Matlab to
these?

Well, first of all it's not a symbolic package.  I've used Matlab and
Mathematica and I find that for numerical calculation Matlab is
significantly faster.  Matlab treats most everything as a vector or
matrix which can be very useful depending on what you want to do.
Plotting with Matlab is very easy and does nice plots, especially good
for data.

I'd say that Mathematica is a much more general package that can
probably do almost everything that Matlab does, but for some things
Matlab does it better.  Matlab also has special Toolboxes for Signal
Processing, Controls, Optimization, etc. which could save you a lot of
work over trying to get Mathematica to do the same.

So in conclusion, the choice depends on what you want to use it for.

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
 Ray Zimmerman            \ 397 Theory Center, Electrical Engineering
                           \ Cornell University, Ithaca NY  14853
 Ray-Zimmerman@cornell.edu  \ Phone: 607-254-8819  Fax: 607-255-9072
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
Newsgroups: sci.math.symbolic
From: creon@nas.nasa.gov (M. Creon Levit)
Subject: commercial version of IBM's "new scratchpad"
Organization: Applied Research Office, NASA Ames Research Center
Date: 8 Sep 92 13:47:29
Reply-To: creon@nas.nasa.gov
Distribution: sci.math.symbolic


The most exciting thing I saw at SIGGRAPH this year was a verson of new
scratchpad running on an IBM r6000 workstation (they had changed the name,
though, and I cant remeber its new name).  Ever since I started reading
about it, I have considered new scratchpad to be the most significant
symbolic computing package since macsyma, and now they are finally letting
it out.  I even saw a preprint of a new book documenting the program.

This program is incredible.  It seems far beyond macsyma-, mathematica-, or
maple-like programs.  I believe this is because it is implemented (and
extended) in an object oriented fashion where the structure of the class
heirarchy is based on the structure of the class heirarchy used in
mathematics itself.  E.g, things like semi-groups, differential forms,
hermitian operators, etc, etc, etc, are distinct datatypes in this system
with the correct relationships between them.

The r6000 implementation had all of the 3D color graphics that we have come
to expect from such packages.  Ports to sun and sgi machines were in the
works. 

I dropped the ball, though, and don't know who to contact about getting it.
If someone could post official information to this newsgroup, I think it
would go over very well.


-- end of message --

Creon Levit

Mail Stop T045-1
NASA Ames Research Center
Moffett Field, California 94035-1000
USA

(415)-604-4403      (phone)
(415)-604-3957      (FAX)
creon@nas.nasa.gov  (Internet)
--

-- end of message --

Creon Levit

Mail Stop T045-1
NASA Ames Research Center
Moffett Field, California 94035-1000
USA

(415)-604-4403      (phone)
(415)-604-3957      (FAX)
creon@nas.nasa.gov  (Internet)
From: las@cunyvms1.gc.cuny.edu
Subject: Chiwriter to Tex converter
Reply-To: las@cunyvms1.gc.cuny.edu
Organization: Computer Center, CUNY Graduate School, New York NY 10036
Date: Tue, 8 Sep 1992 03:38:38 GMT



          I  am Using the Chiwriter version 4. mathematics editor and would 
          like to get the Chiwriter to TEX translator. I would very much
          appreciate from anyone familiar with this converter to:

          1) Tell me which version of tech it converts to.
          2) What is the difference between Turbo TEX and ordinary TEX.
          (by ordinary is meant Latex or AMS TEX.
          3) Also, has anyone an e-mail address for the manufacturers of 
          Chiwriter. The Name of the manufactures follows:

                                 HORTSMANN SOFTWARE

          Thanks in advance. 

          -Bill Baker.
From: cohen@alioth.greco-prog.fr (Henri Cohen)
Newsgroups: sci.math.symbolic
Subject: Three simple Maple questions
Date: 3 Sep 92 09:33:50 GMT
Reply-To: cohen@alioth.greco-prog.fr (Henri Cohen)
Organization: GRECO Programmation du CNRS - Bordeaux,France

I am a Maple beginner and I am stumbling on three questions.
1) I have an expression exp(2*I*k*Pi), where k is a variable.
I would like to expplain to Maple that k is an integer, so that
it can simplify this to 1. Can this be done?

2) In the course of Bessel function computations, several equivalent
integral definitions are used. I am unable to get Maple to evaluate
the integral

int(exp(I*(x*sin(t)-k*t))) 

which should be equal to 2*Pi*BesselJ(k,x).

3) Is it possible to get Maple to differentiate under the integral
sign when the integral cannot be computed explicitly (of course one
could ask Maple to differentiate the integrand and put back the
integral sign, but I would like to know if this can be done directly.

Thank you very much for your help!

	Henri Cohen

cohen@alioth.greco-prog.fr
Newsgroups: sci.math.symbolic
From: rotenber@cco.caltech.edu (James Michael Rotenberry)
Subject: Mma Koch Snowflake in Not. of AMS
Organization: California Institute of Technology, Pasadena
Date: Sun, 13 Sep 1992 20:53:17 GMT



      It appears that I either copied this program incorrectly,
      there was a typo in the publication (please see comment below),
      or the program is not correct.

      According to the 1991 version (2nd edition) of Wolfram's
      Mathematica book, FixedPoint does not allow multiple arguments.

      Can anyone say what is going on?
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

(*  program for a Koch snowflake.  found in the Notices
    of the AMS Vol.39 #7 Sept 92, page 709  *)
KochSnowflake[n_Integer?NonNegative]:=
  Show[Graphics[FixedPoint[
  (#1/.Line[{start_,finish_}]
  :>doline[start,finish]) &,
  {Line[{{0,0},{1/2,Sqrt[3]/2}}],
  Line[{{1/2,Sqrt[3]/2},{1,0}}],
  Line[{{1,0},{0,0}}]},
  n,]],
  AspectRatio->Automatic,PlotRange->All]

doline[start_,finish_]:=
  Module[{vec,normal},
  vec=finish-start;
  normal=Reverse[vec] {-1,1} Sqrt[3]/6;
  {Line[{start,start + vec/3}],
  Line[{start + vec/3,start + vec/2 + normal}],
  Line[{start + vec/2 + normal, start + 2 vec/3}],
  Line[{start + 2 vec/3, finish}]
  }
  ]

KochSnowflake[2]

FixedPoint::argct: FixedPoint called with 4 arguments.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
James M. Rotenberry
rotenber@alumni.caltech.edu
Newsgroups: sci.math.symbolic
From: bfmadore@daisy.uwaterloo.ca (Blair Madore)
Subject: Re: Maple for quantum mechanics?
Organization: University of Waterloo
Date: Fri, 11 Sep 1992 17:17:28 GMT

In article <1992Sep4.053635.12940@midway.uchicago.edu> ppalmer@oskar.uchicago.edu (Patrick Palmer) writes:
>I am trying to use Maple to carry out some quantum mechanical
>calculations.  I cannot get it to expand out a product of two
>polynomials when the multiplication is non-commutative (the
>coefficients of the non-commuting operators can be complex numbers,
>but I don't think this is a problem).  There must be a way do do this,
>but, I looked through the manual and the list of libraries and didn't
>find anything.  Does anyone know how to do this?
>
>Pat Palmer (email: ppalmer@oskar.uchicago.edu)

I think what you want is the commutat package.

It defines &* as noncommutative multiplication with some expansion
and simplification rules.

> readlib(commutat);

proc(f) ... end

> (x+I*y) &* (x-3*y);

							 (x + I y) &* (x - 3 y)

> expand(");

			(x &* x) - 3 (x &* y) + I (y &* x) - 3 I (y &* y)


I hope this helps.
See ?commutat for more info.


Newsgroups: sci.math.symbolic
From: hmarvel@magnus.acs.ohio-state.edu (Howard P Marvel)
Subject: plots and eval
Organization: The Ohio State University
Date: Thu, 10 Sep 1992 16:40:17 GMT

Consider the following series of statements in Maple:

c := proc (alpha,beta) if signum(alpha+beta)=1 then alpha+ beta else 0 fi en\
d;
c(a,b);
a:=1;
b:=1;
c(a,b);
plot3d(c(x,y),x=0..1,y=0..1);

The first sets up a proc that returns alpha + beta if alpha + beta is
a positive real. However, if alpha and beta are variables, signum
cannot evaluate the expression, and the proc returns 0. The first call
c(a,b) returns 0 and the second returns 2. Now consider the plot
statement. This should yield values from 0 to 2, right? Instead,
signum fails and all plotted values are 0. My question is, is there a
way to force Maple to evaluate c for the values in question and to
plot the values?  

Thanks in advance for any suggestions.
From: fanchiot@acf3.NYU.EDU (Sergio Fanchiotti)
Newsgroups: sci.math.symbolic
Subject: MapleV: limit crashes... an old bug?
Date: 8 Sep 92 14:35:00 GMT
Organization: New York University




	I hope this is not one of those well known bugs. If so please
	send me a pointer to a FEB (Frequantly Encountered Bug) list!

	Playing with MapleV I found out that sometimes it crashes
	pretty badly trying a simple limit, it simply runs out of
	memory!

> limit(ln(abs(x))*x,x=0) ;
bytes used=1000436, alloc=786288, time=9.883
/usr/bin/maple: 15422 Memory fault11.0u 2.3s 0:36elap 36%cpu (243t+820ds+1063avg+832max)kb (15i+13o)ev (10maj+66min)pf 0swaps

If we try with the right condition: sometimes it works some it doesn't.

> limit(ln(abs(x))*x,x=0,right) ;
bytes used=1000008, alloc=786288, time=10.283
/usr/bin/maple: 15448 Memory fault11.4u 2.1s 0:38elap 34%cpu (242t+817ds+1059avg+832max)kb (28i+12o)ev (10maj+66min)pf 0swaps

From the left it also crashes...

> limit(ln(abs(x))*x,x-=0,left) ;
bytes used=1000004, alloc=786288, time=10.683
/usr/bin/maple: 15474 Memory fault11.9u 2.8s 0:49elap 29%cpu (247t+809ds+1056avg+838max)kb (43i+13o)ev (11maj+66min)pf 0swaps


	Does anyone know why this crashes Maple. Also, Mathematica won't
	do it, but it does not crash..

					Saludos,
						...Sergio.