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Re: Re: inverting Laplace transforms

  • To: mathgroup at smc.vnet.net
  • Subject: [mg95168] Re: [mg95132] Re: inverting Laplace transforms
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Wed, 7 Jan 2009 18:56:23 -0500 (EST)
  • Organization: Mathematics & Statistics, Univ. of Mass./Amherst
  • References: <gjv78b$p41$1@smc.vnet.net> <200901070911.EAA25449@smc.vnet.net>
  • Reply-to: murray at math.umass.edu

Yes, the InverseLaplaceTransform command is available, but when I tried

   InverseLaplaceTransform[Sqrt[s + a]/(Sqrt[s] (s - b)), s, t]

in Mathematica 7.0, after a couple of minutes it just returns the 
expression unevaluated.

Note that, unlike the case with LaplaceTransform, 
InverseLaplaceTransform does not seem to allow an Assumptions option.

Sjoerd C. de Vries wrote:
> Dear Leslaw,
> 
> I'll assume you don't have a copy of Mathematica with you, otherwise I
> fail to understand why you haven't looked this up yourself  in the
> excellent electronic documentation.
> 
> Actually, there isn't an excuse at all because it's online as well:
> http://reference.wolfram.com/mathematica/guide/Mathematica.html
> 
> Found in 2 seconds:
> http://reference.wolfram.com/mathematica/ref/InverseLaplaceTransform.html
> 
> Cheers -- Sjoerd
> 
> 
> On Jan 6, 11:11 am, Leslaw Bieniasz <nbbie... at cyf-kr.edu.pl> wrote:
>> Hello,
>>
>> I need to invert a few expressions representing Laplace transforms. I hav=
> e heard that MATHEMATICA can be used
>> for this purpose. Can anybody tell me how to do this?
>>
>> For example, I need to find a function f(t) for which the
>> Laplace transform F(s) is
>>
>> F(s) = Sqrt[s + a]/(Sqrt[s] * (s - b))
>>
>> where a > 0 and b > 0 are constants.
>>
>> Leslaw
> 
> 

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305


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