Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2000
*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 2000

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

Search the Archive

Another strange bug in Mathematica 4.0's Integrate

  • To: mathgroup at smc.vnet.net
  • Subject: [mg25251] Another strange bug in Mathematica 4.0's Integrate
  • From: Hendrik van Hees <h.vanhees at gsi.de>
  • Date: Sun, 17 Sep 2000 04:47:30 -0400 (EDT)
  • Organization: GSI Darmstadt
  • Sender: owner-wri-mathgroup at wolfram.com

Here you see another strange bug in Integrate. 

In[1]:= Integrate[Sqrt[(r-x)(r+x)],{x,-r,r},Assumptions->{r>0}]

                   2
        Pi r Sqrt[r ]
Out[1]= -------------                (WRONG)
              4

while

In[2]:= Integrate[Sqrt[r^2-x^2],{x,-r,r},Assumptions->{r>0}]

            2
        Pi r
Out[2]= -----     (correct)
          2

and please don't tell me that there is an ambiguity concerning the path
of integration in the complex plane. It is very clear that the integral
is meant to be taken along the real axis from -r to r, because if
Integrate would be a complex path integral the user should be able to
specify this path of integration!

-- 
Hendrik van Hees		Phone:  ++49 6159 71-2751
c/o GSI-Darmstadt SB3 3.183	Fax:    ++49 6159 71-2990
Planckstr. 1			mailto:h.vanhees at gsi.de
D-64291 Darmstadt		http://theory.gsi.de/~vanhees/index.html


  • Prev by Date: RE: Testing the Head of List Elements
  • Next by Date: Re: Testing the Head of List Elements
  • Previous by thread: Re: Fixing options to Cell expressions
  • Next by thread: Re: Another strange bug in Mathematica 4.0's Integrate