Re: double integral problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg112547] Re: double integral problem*From*: Simon <simonjtyler at gmail.com>*Date*: Sun, 19 Sep 2010 05:39:45 -0400 (EDT)*References*: <i727k7$eup$1@smc.vnet.net>

On Sep 18, 9:25 pm, Regina <regina.lagra... at googlemail.com> 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 Hi Regina, Do you want something like In[1]:= With[{a=1}, NIntegrate[Exp[-(a/(4*x)) - 4*x], {Q, 0, 1},{x, 0, Q}]] Out[1]= 0.0391749 Simon