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Re: How to NSolve equation which involves NIntegrate?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg120081] Re: How to NSolve equation which involves NIntegrate?
  • From: Ted Sariyski <tsariysk at craft-tech.com>
  • Date: Fri, 8 Jul 2011 04:50:18 -0400 (EDT)
  • References: <201106250929.FAA20235@smc.vnet.net> <201106271131.HAA07842@smc.vnet.net> <201106281155.HAA21486@smc.vnet.net> <002f01cc35a6$3dd69ca0$b983d5e0$@dahl@telia.com> <201106290929.FAA02776@smc.vnet.net> <2A0AA73D3621CE4BBE6BAEC6FEB4661E01E0BD0A@MBX01.seas.harvard.edu> <201107071131.HAA15319@smc.vnet.net> <op.vx86doa8tgfoz2@bobbys-imac.local>

I am sorry, I should made up an example. Here it is:

f[a_] := NIntegrate[Sin[a x], {x, 0, 1}]
g[a_] := a*a
NSolve[f[a] == g[a], a]

Out[]: NIntegrate::inumr: "The integrand Sin[a x] has evaluated to 
non-numerical values for all sampling points in the region with 
boundaries {{0,1}}."

Thanks,
--Ted

On 7/7/2011 10:26 AM, DrMajorBob wrote:
> You left out the definition of h, so how can we possibly tell you why 
> it evaluates to non-numerical values?
>
> Bobby
>
> On Thu, 07 Jul 2011 06:31:38 -0500, Ted Sariyski 
> <tsariysk at craft-tech.com> wrote:
>
>> Hi,
>> I need  a numerical solution for a system of equations which involve
>> numerical integrals. For one parameter the equation would be:
>>
>> f[a]==g[a]
>>      where
>> f[a_]:=NIntegrate[h[x, a] , {x, x1, x2}]
>>
>> NSolve returns: "The integrand  has evaluated to non-numerical values".
>>
>> Is there a built-in procedures for this type of problems or I need to
>> make explicit iterations?
>>
>> Thanks in advance,
>> --Ted
>>
>>
>>
>>
>>
>
>



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