MathGroup Archive 2009

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Different results with FourierTransform[]


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
> 
> 


  • Prev by Date: Re: Two Notebooks Open at the Same Time
  • Next by Date: Re: identical rows in tables
  • Previous by thread: Re: Different results with FourierTransform[]
  • Next by thread: Re: Different results with FourierTransform[]