Mathematica 9 is now available
Student Support Forum
-----
Student Support Forum: 'Integrate fails on elliptic integral?' topicStudent Support Forum > General > Archives > "Integrate fails on elliptic integral?"

Next Comment >Help | Reply To Topic
Author Comment/Response
Kevin Watkins
01/17/04 5:04pm

I don't understand the following behavior of Integrate[]. The function to be integrated is real and continuous over the domain of integration, but the result provided by Integrate is not real. A branch cut problem in Integrate's implementation?

Many similar integrands seem to fail in the same way, and the solutions provided by Mathematica for more general elliptic integrals (where the parameters and bounds of integration are variables rather than specific integers) also seem to fail.

Hopefully someone here knows what the issue is. (This is the student version of Mathematica 5.0.0.0.)

Kevin

In[1]:=
Integrate[((x+2)(x+1)(x^2-2x+2))^(-1/2),{x,0,2}]//N

Out[1]=
-2.27301-1.18292 \[ImaginaryI]

In[2]:=
NIntegrate[((x+2)(x+1)(x^2-2x+2))^(-1/2),{x,0,2}]

Out[2]=
0.763121

URL: ,

Subject (listing for 'Integrate fails on elliptic integral?')
Author Date Posted
Integrate fails on elliptic integral? Kevin Watkins 01/17/04 5:04pm
Re: Integrate fails on elliptic integral? Dan Margolis 01/23/04 03:54am
Re: Integrate fails on elliptic integral? Kevin Watkins 02/28/04 3:08pm
Next Comment >Help | Reply To Topic