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Re: double integral problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg112535] Re: double integral problem
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Sun, 19 Sep 2010 05:37:33 -0400 (EDT)

I don't think you can expect to have Mathematica carry out a numerical 
integration when it involves a non-numeric quantity a.

Try this, with the integration variables reversed:

   NIntegrate[Exp[-a/(4 x)-4 x]/.a->1,{Q,0,1},{x,0,Q}]


On 9/18/2010 7:26 AM, Regina wrote:
> hi there,
> im trying to evaluate the following double integral:
> N[Integrate[Integrate[Exp[-a/(4 x) - 4 x], {x, 0, Q}], {Q, 0, 1}]]
>
> and set a to 1 or some other non-zero number.
>
> but for some reason, mathematica only gives me error messages. what am
> i doing wrong?
> best. regina
>

-- 
Murray Eisenberg                     murray at math.umass.edu
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University of Massachusetts                413 545-2859 (W)
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