Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*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 2004

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

Search the Archive

Question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg46433] Question
  • From: jjaeckel <jjaeckel at ix.urz.uni-heidelberg.de>
  • Date: Wed, 18 Feb 2004 00:36:57 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Hi!

I have a question about Integrate:

If I want to compute a completely real integral, e.g.

Integrate[(2*p^2*q^2*y^2 + p^3*q*y - p^2*q^2 + p*q^3*y + q^4)*1/(q^2)*1/(
           q^2 + 2*p*q*y + p^2) - 1, {y, -1, 1}, {q, 0, ?}]

I quite often get a complex result, e.g. in this case
(for Mathematica 5.0)


(-\Pi^2+8*Log[-p]+8*Log[p])/(8*Sqrt[1/(p^2)])

Moreover, in Version 4.2 seems to produce a different result. E.g. if I 
evaluate the above result for p=1 I get

-(1/8)*Pi*(-8*I+Pi)

but if I do the same calculation using Mathematica 4.2 I get

-(1/2)*Pi*(I+Pi)

What did I do wrong?

Sorry if this question isn't new...

Greetings
     Joerg


  • Prev by Date: Re: No Output, No Error
  • Next by Date: Re: Can Mathematica Ver 5 Import ESRI *.shp, *.shx and DBase *.dbf files??
  • Previous by thread: Re: Re: Simplify and Gather Terms in a Polynomial
  • Next by thread: A New Kind of Science Online