From harper@kauri.vuw.ac.nz Mon Jan 11 22:35:46 CST 1999 Article: 18375 of sci.math.symbolic Path: news.math.niu.edu!husk.cso.niu.edu!vixen.cso.uiuc.edu!logbridge.uoregon.edu!su-news-hub1.bbnplanet.com!news.gtei.net!newsfeed.concentric.net!newsfeed.clear.net.nz!news.wlg.netlink.net.nz!harper From: harper@kauri.vuw.ac.nz (John Harper) Newsgroups: sci.math.symbolic Subject: Re: integration error Date: 11 Jan 1999 20:41:08 GMT Organization: Victoria University of Wellington, New Zealand Lines: 23 Message-ID: <916087266.675264@bats.mcs.vuw.ac.nz> References: <76tdc2$bqs$1@gannett.math.niu.edu> NNTP-Posting-Host: bats.mcs.vuw.ac.nz Cache-Post-Path: bats.mcs.vuw.ac.nz!harper@kauri.vuw.ac.nz X-Cache: nntpcache 2.3.2.1 (see http://www.nntpcache.org/) Xref: news.math.niu.edu sci.math.symbolic:18375 In article <76tdc2$bqs$1@gannett.math.niu.edu>, Dave Rusin wrote: >In article , >nobody wrote: >>I would like to have a few examples of functions f(x) for which >>Maple, Mathematica, etc. produce a wrong integral for. >>Any takers? > >I like to present such examples to my students, who are prone to accept >calculator results blindly; I collected some of them into a file > http://www.math.niu.edu/~rusin/teaching-math/calc.errors Not in that file but reported a few months ago by someone whose name I have unfortunately mislaid (apologies!): Maple V.4 and V.5 give wrong answers for int(Int(f(x)*y, x=a..b), y); (unless f(x) = constant!) If you change Int to int the answer is correct if f(x) is nonzero on [a,b], but it is bizarrely presented.) I seem to recall someone saying at the time Maple V.5 does the same. John Harper, School of Mathematical and Computing Sciences, Victoria University, Wellington, New Zealand e-mail john.harper@vuw.ac.nz phone (+64)(4)471 5341 fax (+64)(4)495 5045