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Re: Re: NSum: badly missed Option


A short remark
In the exampls it shoud be x^20 and not x20 in order to repeat the results
yehuda


On 5/10/05, antononcube <antononcube at gmail.com> wrote:
> Alan wrote:
> > "Chris Chiasson" <chris.chiasson at gmail.com> wrote in message
> > news:d5j5ob$qf3$1 at smc.vnet.net...
> > > Try SetOptions on NIntegrate before the NSum call.
> >
> > Excellent. Thanks for the solution!
> >
> > regards,
> > alan
> 
> Nested Method option can be used in NSum.
> 
> For example:
> 
> In[1]:= NSum[1/(x20*Sin[x]^2), {x, 2, Infinity}, Method -> NIntegrate]
> 
> NIntegrate::ncvb:
>   NIntegrate failed to converge to prescribed accuracy after 7
>     recursive bisections in x near x = 18.8764.
> 
> Out[1]= 1.16782 10^-6
> 
> In[2]:= NSum[1/(x20*Sin[x]^2), {x, 1, Infinity}, Method -> {NIntegrate,
> MaxRecursion -> 100}]
> 
> NIntegrate::slwcon:
>   Numerical integration converging too slowly; suspect one of the
> following:
>    singularity, value of the integration being 0, oscillatory
> integrand, or
>    insufficient WorkingPrecision. If your integrand is oscillatory try
> using
>    the option Method->Oscillatory in NIntegrate.
> 
> Out[2]= 1.41228
> 
> Anton Antonov
> Wolfram Research, Inc.
> 
>


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