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MathGroup Archive 2004

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Re: Problem with FourierTransform

  • To: mathgroup at smc.vnet.net
  • Subject: [mg49929] Re: Problem with FourierTransform
  • From: "Steve Luttrell" <steve_usenet at _removemefirst_luttrell.org.uk>
  • Date: Fri, 6 Aug 2004 03:09:54 -0400 (EDT)
  • References: <cetevp$6hf$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

This works OK in version 5.0.1.


FourierTransform[Sin[t^2]/2 + 1/2, t, w]

gives

Sqrt[Pi/2]*DiracDelta[w] + (1/4)*(Cos[w^2/4] - Sin[w^2/4])

and
FourierTransform[Sin[t^2/c]/2 + 1/2, t, w]

gives

Sqrt[Pi/2]*DiracDelta[w] - (I*(Cos[(c*w^2)/4] -
I*Sin[(c*w^2)/4])*(Sqrt[I/c] - Sqrt[-(I/c)]*Cos[(c*w^2)/2] +
     (-(I/c))^(3/2)*c*Sin[(c*w^2)/2]))/(4*Sqrt[2]*Sqrt[1/c^2])

which reduces to the first case thus

FullSimplify[% /. c -> 1]

Steve Luttrell

"Oliver" <ofr at interims.de> wrote in message
news:cetevp$6hf$1 at smc.vnet.net...
> Why doesn't this work:
> This FT can be computed without problems
>   FourierTransform[Sin[t^2]/2+1/2]
> But this one
>   FourierTransform[Sin[t^2/c]/2+1/2]
> gives error:
>   Simplify::"fas": "Warning: self-contradictory
>   assumptions encountered."
> Why?
>
> Oliver
>



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