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