Re: Different results with FourierTransform[]
- To: mathgroup at smc.vnet.net
- Subject: [mg97633] Re: Different results with FourierTransform[]
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Tue, 17 Mar 2009 05:01:34 -0500 (EST)
- Organization: Uni Leipzig
- References: <gpl5sh$ou6$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
Hi,
and more surprising I have a third one, and this is the
correct one
Integrate[Tanh[x]*Exp[I*x*p], {x, -Infinity, Infinity}]
gives
Integrate::idiv:Integral of E^(I*p*x) Tanh[x] does not converge on
{-Infinity,Infinity}
Regards
Jens
Wieland Brendel wrote:
> Dear reader,
> I somewhat stumbled over the following behaviour of mathematica: I tried
> to calculate the fouriertransform of Tanh[x]. I did this in two ways:
>
> 1. Directly:
> InverseFourierTransform[Tanh[x], x, p]
>
> 2. Indirectly:
> InverseFourierTransform[Tanh[B x], x, p]
>
> where I set B -> 1 in the end.
>
> However, the result between the two approaches differs: Whereas in the
> first approach I get a complex number (with both real and imaginary part
> being non-zero for almost all values of p), the result in the second
> approach yields NO real part; the imaginary part however is the same as
> in the first approach. Is there any explanation for this behaviour?
>
> Thanks a lot in advance! I am really stuck with that...
> Wieland
>
>