Services & Resources / Wolfram Forums
MathGroup Archive
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2007

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

Search the Archive

Integrals involving square roots

  • To: mathgroup at
  • Subject: [mg73854] Integrals involving square roots
  • From: "Andre Giroux" <giroux at>
  • Date: Fri, 2 Mar 2007 06:27:45 -0500 (EST)

Hi All.
Mathematica is very unreliable when it computes integrals involving square 
roots. The following were obtained running Mathematica 5.2 and 5.1 with 
Windows XP pro:

\!\(\[Integral]\_\(-3\)\%3\(\[Integral]\_\(-\@\(9 - x\^2\)\)\%\(\@\(9 - 
\x\^2\)\)\(\[Integral]\_0\%\(y - 3\)2 y \[DifferentialD]z \[DifferentialD]y 
\!\(\(81\ \[Pi]\)\/2\)
\!\(\[Integral]\_0\%2\(\[Integral]\_\(-R\)\%R\( Rz\^2\/\@\(R\^2 - x\^2\)\) 
\\[DifferentialD]x \[DifferentialD]z\)\)
\!\(\(-2\)\ \[Pi]\ Rz\^2\)

In both cases, the sign is wrong and, with the first integral, it is not 
obvious. Interestingly, Mathematica 5.0 computes these integrals correctly. 
So beware!

  • Prev by Date: Re: Sort with -Infinity fails
  • Next by Date: Regression
  • Previous by thread: Re: Unexpected message 2
  • Next by thread: Re: Integrals involving square roots