RE: Integrate Problem
- To: mathgroup at smc.vnet.net
- Subject: [mg40562] RE: [mg40502] Integrate Problem
- From: "David Park" <djmp at earthlink.net>
- Date: Thu, 10 Apr 2003 03:38:49 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Stewart,
One method is the following...
answer =
Integrate[1/Pi^2 1/(1 + x^2 + y^2 + z^2)^2, {z, -Infinity, Infinity}];
Re[answer] // ComplexExpand
Im[answer] // ComplexExpand
1/(2*Pi*(1 + x^2 + y^2)^(3/2))
0
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
From: Stewart Mandell [mailto:stewart at rentec.com]
To: mathgroup at smc.vnet.net
When I run
Integrate[1/Pi^2 1/(1 + x^2 + y^2 + z^2)^2, {z, -Infinity, Infinity},
Assumptions -> {Im[x] == 0, Im[y] == 0, Im[z] == 0}]
I get
(I*(Log[-(I/Sqrt[1 + x^2 + y^2])] -
Log[I/Sqrt[1 + x^2 + y^2]]))/
(2*Pi^2*(1 + x^2 + y^2)^(3/2))
I would like
1/(2*Pi ) 1/(1 + x^2 + y^2)^3/2
for an answer. How do I get Mathematica to forego the complex
answer?
thanks, Stewart