More Integral Trouble
- To: mathgroup <mathgroup at yoda.physics.unc.edu>
 - Subject: More Integral Trouble
 - From: Roberto Sierra <73557.2101 at compuserve.com>
 - Date: 19 Jul 93 22:06:16 EDT
 
I encountered another problematic integral the other day -- this one
MMA could not evaluate (or reject) after crunching for a full 48 hours
over the weekend and consuming 16MB of memory in the process.  I'm
using MMA 2.03 for the Mac.  This type of equation comes about from
electrostatic field theory.  The variables sigma, x, y, z and r are
considered constants within the integral.  Shouldn't MMA give up much
sooner??
Timing[Integrate[
        (sigma Sqrt[r^4 Sin[theta]^2] (x - r Cos[phi] Sin[theta])) /
            ((z - r Cos[theta])^2 + (x - r Cos[phi] Sin[theta])^2 +
             (y - r Sin[phi] Sin[theta])^2)^(3/2),
        {phi,0,2Pi},{theta,-Pi,Pi}
]]
-- Roberto Sierra
   Tempered MicroDesigns