Re: Re: NSum: badly missed Option

• To: mathgroup at smc.vnet.net
• Subject: [mg56974] Re: [mg56938] Re: NSum: badly missed Option
• From: yehuda ben-shimol <bsyehuda at gmail.com>
• Date: Wed, 11 May 2005 05:25:20 -0400 (EDT)
• References: <200505070816.EAA20223@smc.vnet.net> <d5j5ob\$qf3\$1@smc.vnet.net> <d5kb13\$2at\$1@smc.vnet.net> <200505100743.DAA08420@smc.vnet.net>
• Reply-to: yehuda ben-shimol <bsyehuda at gmail.com>
• Sender: owner-wri-mathgroup at wolfram.com

```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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