Re: input without output
- To: mathgroup at smc.vnet.net
- Subject: [mg39116] Re: input without output
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Thu, 30 Jan 2003 01:05:54 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <b184f1$kqe$1@smc.vnet.net>
- Reply-to: kuska at informatik.uni-leipzig.de
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
you should fix you StandardForm[] input it is
InverseFourierTransform[
Sum[DiracDelta[1000(-1 + 10^(fHat/c))/b - f], {fHat, 0, N}], f, t]
and it is no wonder that Mathematica can't find a result because
a) N[] is used to convert a exact number into a floating point value
b) N has no value, espacial in you expression it can be 0
c) Mathematica must Solve[1000(-1 + 10^(fHat/c))/b - f== 0,fhat]
and find out if the solution lies between 0 and N and this
can't be done without a knowlege about N
Regards
Jens
Matt Flax wrote:
>
> Thefollowing input generates no answer (mathematica 4.2) :
>
> (*I re-write it so it is easier to read*)
>
> InverseFourierTransform[
> Sum[
> DiracDelta[1000(-1 + 10^(fHat/c))/b - f],
> (fHat = 0),N],
> f,t]
>
> (*Which is the same as*)
> Notebook[{
> Cell[BoxData[
> \(
> InverseFourierTransform[\[Sum]\+\(fHat = 0\)\%N DiracDelta[
> 1000 \((\(-1\) + 10^\(fHat\/c\))\)\/b - f], f,
> t]\)], "Input"]
> },
> FrontEndVersion->"4.2 for X",
> ScreenRectangle->{{0, 1280}, {0, 1024}},
> WindowSize->{959, 890},
> WindowMargins->{{0, Automatic}, {Automatic, 0}}
> ]
>
> Any ideas ?
> thanks
> Matt
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