Re: A problem with an integral
- To: mathgroup at smc.vnet.net
- Subject: [mg32806] Re: A problem with an integral
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Thu, 14 Feb 2002 01:43:20 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <a4aurc$buv$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
no you code is right but Mathematica take a different
path to compute
Integrate[Sin[x y], {y, 0, x}]
with it's singularity at x==0
Regards
Jens
WhoamI wrote:
>
> Hi everybody, I have a problem with the next integral
>
> Integrate[Sin[x y],{x,0,1},{y,0,x}]
>
> that after expanding and factoring yields:
>
> \!\(1\/4\ \((EulerGamma - 2\ CosIntegral[1])\)\)
>
> and evaluating this I have -0.024398
>
> To be sure about the answer I taked it other way:
>
> Integrate[
> TrigFactor[Integrate[Sin[x y], {y, 0, x}]]
> , {x, 0, 1}]
>
> which yields
>
> \!\(1\/2\ \((EulerGamma - CosIntegral[1])\)\)
>
> and evaluating this I have 0.119906
>
> Since I evaluated this integrals not numerically I
> don't understand why the answers are different. Is
> there something wrong with my code?. I would thanks a
> lot for your answers...
>
> Cesar Guerra
> Secc. Fisica PUCP-Lima
>
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