Re: Mathematica does this integral wrong?
- To: mathgroup at smc.vnet.net
- Subject: [mg43187] Re: Mathematica does this integral wrong?
- From: "M" <cgi2 at zipmail.com>
- Date: Sun, 17 Aug 2003 04:27:58 -0400 (EDT)
- References: <bhkl3t$pde$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
"M" <cgi2 at zipmail.com> wrote in message news:bhkl3t$pde$1 at smc.vnet.net... > I have a sum of 2 definite integrals. The integrals are in 1 variable. The > integrand has several parameters. > I tried doing the integration 3 ways: > > 1) Put in the parameter values into the integrand itself and then perform > the integral. > 2) Do the integration first and then evaluate the result for a certain set > of parameter values. > 3) Put in the parameter values into the integrand itself and then perform > the integral Numerically. > > I get different results; 1) and 3) agree while 2) gives a different result. > I think 2) is incorrect; the result should be positive as far as I can see > but 2) is negative. > > I'm attaching a zip of the notebook file. I hope a less than 3kb attachment > is okay in this group. > > [Contact the author to get the attachment - moderator] > > Thanks > -M Hmm...the attachment appears to have been moderated out...I cant find a faq for this group; I looked at http://www.faqs.org/faqs/by-newsgroup/comp/ . It seems to me that preventing postings of notebooks in a mathematica group limits its utility significantly. Notebooks are generally tiny files. Mine was 2.8kb - hardly bigger than a page of text. [All attachments are moderated out and will continue to be. Attachments are just too "dubious" these days and many spam filters cut them out anyway. If you want to show people a notebook, either put it on the web and include a URL or put the notebook - if it is small - in the test of the email in ascii form. - moderator] Anyway, I tried it on Mathematica 5 (I'd been using 4.1) and the problem went away. Presumably this was indeed a Mathematica 4.1 bug. -M