Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site randvax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!vax135!cornell!uw-beaver!tektronix!hplabs!sdcrdcf!randvax!Bob CavinessFrom: 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 References: <256@watmum.UUCP> Sender: lseward@randvax.UUCP Distribution: net Organization: Rand Corp., Santa Monica Lines: 100 > (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 */ ----forwarded message--- Received: from UDel-Dewey.ARPA by rand-unix.ARPA; Tue, 20 Aug 85 14:00:50 pdt Message-Id: <8508202100.AA21766@rand-unix.ARPA> Received: from localhost by .UDel-Dewey.ARPA id a027015; 20 Aug 85 16:53 EDT 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 ------- End of Forwarded Message