Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1992
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1992

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: A negative volume!

  • To: mathgroup at yoda.physics.unc.edu
  • Subject: Re: A negative volume!
  • From: ags at seaman.cc.purdue.edu (Dave Seaman)
  • Date: Sat, 14 Mar 92 11:38:19 -0500

>> >Anybody have any suggestions on how to avoid this kind of problem?
>
>> A change in the order of integration seems to do the trick.  
>
>Doing the integral by hand also does the trick.  I think the question
>is how to increase the reliability of Mathematica's definite
>integrals, not to get the answer to one particular integral.
>
>Silvio

I fail to see any practical difference between the observations "A change in
order works." and "Integrating by hand words."  Both point out in unmistakeable
terms that there is a problem in Integrate[], and neither offers a solution.

My observation was intended to offer some insight into what went wrong.  More
precisely, the original poster has pointed out that the third integral in his
computation leads to an antiderivative that is piecewise continuous, with
discontinuities at both endpoints of the interval of integration, and
Mathematica seems to have used the wrong one-sided limits.

Dave





  • Prev by Date: PostScript
  • Next by Date: Re: PostScript
  • Previous by thread: Re: A negative volume!
  • Next by thread: Third Annual Conference on College Mathematics