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Re: How can I get this spiked Integral evaluated???

  • To: mathgroup at smc.vnet.net
  • Subject: [mg72003] Re: How can I get this spiked Integral evaluated???
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Thu, 7 Dec 2006 06:26:23 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <el687j$2pv$1@smc.vnet.net>
  • Reply-to: kuska at informatik.uni-leipzig.de

Hi,

try
Integrate[Exp[-x^2], {x, -900, 1000}]

witout the N* and finaly, when you have got the anlytical result
use N[]

Regards
   Jens

Zeno wrote:
> This is an integral with a spike that is not in the middle of the
> integral range. Here is the integral...
> 
> NIntegrate[Exp[-x^2], {x, -900, 1000}]
> 
> Mathemtaica 5.2.2 gives this error message....
> 
>  "Numerical \integration stopping due to loss of precision. Achieved
> neither the requested \PrecisionGoal nor AccuracyGoal; suspect one of
> the following: highly \oscillatory integrand or the true value of the
> integral is 0. If your \integrand is oscillatory on a (semi-)infinite
> interval try using the option \Method->Oscillatory in NIntegrate. 
> More?
> 
> However, to use the option "Method->Oscillatory" one of the bounds of
> the integral must be infinity, so that would not work here. How do I
> get it to to the integral in the range -900 to 1000??
> The correct answer is 1.77245.
> 


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