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From: Bob Caviness 
Newsgroups: net.math.symbolic
Subject: Re: Bug in Macsyma's definite integration ?
Message-ID: <2660@randvax.UUCP>
Date: Wed, 21-Aug-85 12:33:10 EDT
Article-I.D.: randvax.2660
Posted: Wed Aug 21 12:33:10 1985
Date-Received: Sun, 25-Aug-85 13:25:24 EDT
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> (c1) integrate( exp(-t)/(1+t), t, 0, infinity );
> INTEGRAL IS DIVERGENT
> 
> /* This is wrong.  Have I input the problem incorrectly ? */
> /* Also, after 10 minutes on the following problem. */
> 
> (c2) integrate( exp(-t)/(1+t^(3/2)), t, 0, infinity );
> NAME STACK OVERFLOW
> 
> /* Am using the latest version on a VAX running Berkely UNIX BSD 4.2 */

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Subject: Reply to message re bug in Macsyma's definite integration
Date: 20 Aug 85 16:53:16 EDT (Tue)
From: Bob Caviness 


In response to Michael B. Monagan's message I tried his integrals and
got the following using macsyma version 309 on a Vax 785.
It's not very helpful, but at least it's not incorrect.

Script started on Tue Aug 20 13:12:03 1985

% macsyma

This is UNIX MACSYMA Release 309.1.
(c) 1976,1984 Massachusetts Institute of Technology.
All Rights Reserved.
Enhancements (c) 1984 Symbolics, Inc. All Rights Reserved.
Type describe(trade_secret); to see Trade Secret notice.
Type exec("man macsyma"); for help.

/usr/macsyma.309/macsyma.l being loaded.

Batching the file /users/2125/13772/macsyma.mac
Batching done.

(c1) %e  exp(-t)/(t+1);

Time= 50 msec.

                                       - t
                                     %e
(d1)                                 -----
                                     t + 1

(c2) integrate(%,t,0,inf);

Totaltime= 16233 msec.  GCtime= 4666 msec.

                                  inf
                                 /      - t
                                 [    %e
(d2)                             I    ----- dt
                                 ]    t + 1
                                 /
                                  0

(c3) exp(-t)/(1+(t)   t^^(3/2));

Time= 50 msec.

                                      - t
                                    %e
(d3)                              ----------
                                   <3/2>
                                  t      + 1

(c4) exp   edit(c3);
[starting edit]

Time= 166 msec.

                                      - t
                                    %e
(d4)                               --------
                                    3/2
                                   t    + 1

(c5) integrate(5,  %,t,0,int f);

Totaltime= 12033 msec.  GCtime= 4700 msec.

                                inf
                               /       - t
                               [     %e
(d5)                           I    -------- dt
                               ]     3/2
                               /    t    + 1
                                0

(c6) quit();
% ^D
script done on Tue Aug 20 13:15:37 1985


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