another integral problem
- To: mathgroup at smc.vnet.net
- Subject: [mg32577] another integral problem
- From: Bradley Stoll <BradleyS at Harker.org>
- Date: Wed, 30 Jan 2002 03:18:50 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Awhile ago I had a problem with a triple integral. Now, I've got troubles
with a single integral. I'm sure that it has something to do with 'how' Mathematica
finds integrals, but if someone could clue me in...
Integrate[Abs[x^2 Cos[x]-x^3 + x,{x,0,1.1983}] and Integrate[Abs[x^2
Cos[x]-x^3 + x,{x,0,1.19836]. From appearance, you might guess that these
should be pretty close. The first is pos., while the 2nd is neg, even
though the integrand is non-neg. FYI, 1.1983 is an approx. to x^2
Cos[x]=x^3 -x. What's interesting, is that when you use a 'better' approx.,
the result is neg. Now, with NIntegrate, there is no problem. Please
advise.
Bradley Stoll