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MathGroup Archive 1999

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Question on multiple variables FourierTransformation.

  • To: mathgroup at
  • Subject: [mg18250] Question on multiple variables FourierTransformation.
  • From: Weilou Gao <wxg124 at>
  • Date: Thu, 24 Jun 1999 14:24:28 -0400
  • Sender: owner-wri-mathgroup at

Dear Collegue,

I carry out Fourier Tranformation of second derivative of a function.

When the function is defined as u[x],
     FourierTransform[D[u[x],{x,2}],x,k]    ---->  -k^2
FourierTransform[u[x], x, k]

But if I introduce another variable and write the function as u[x,t],
carry out same transformation,

      FourierTransform[D[u[x,t],{x,2}],x,k]    gives me only
FourierTransform[u(2, 0)(x, t), x, k]    which is supposed to be
-k^2 FourierTransform[u[x,t], x, k]

I am wondering if Mathematica always defautly considers the variables
dependent so it cannt work out the Fourier transform with mutliple

Thanks for your help.

Weilou Gao

ESM Department
The PennStateUniv. (Univ. Park)
Tel: 1-814-863-2737(O)
Email: wxg124 at

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