Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2003
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2003

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

Search the Archive

FourierTransform bug?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg44126] FourierTransform bug?
  • From: "Dr. Wolfgang Hintze" <weh at snafu.de>
  • Date: Thu, 23 Oct 2003 07:15:54 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Hi all,
What happens here in Mathematica 4.0?

The sum of two terms is not correctly Fourier-transformed

In[46]:=
FourierTransform[q + p*Exp[-(I*t*v)], t, x]

Out[46]=
0

But each term separately is ok:

In[57]:=
xx = FourierTransform[q, t, x]

Out[57]=
Sqrt[2*Pi]*q*DiracDelta[x]

In[48]:=
yy = FourierTransform[p*Exp[-I*t*v], t, x]

Out[48]=
p*Sqrt[2*Pi]*DiracDelta[v - x]

In[49]:=
xx + yy

Out[49]=
p*Sqrt[2*Pi]*DiracDelta[v - x] +
   Sqrt[2*Pi]*q*DiracDelta[x]

If instead of the Exp[] function we take powers of t it works fine as well:

In[63]:=
FourierTransform[q + p*t, t, x]

Out[63]=
Sqrt[2*Pi]*q*DiracDelta[x] - I*p*Sqrt[2*Pi]*
    Derivative[1][DiracDelta][x]

Any hint is greatly appreciated,

Wolfgang


  • Prev by Date: Re: Unknown option PlotLegend in Plot
  • Next by Date: NSolve and SplineFit
  • Previous by thread: Re: Integrating over area of intersection
  • Next by thread: NSolve and SplineFit