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Re: InverseLaplaceTransform

• To: mathgroup at smc.vnet.net
• Subject: [mg100292] Re: InverseLaplaceTransform
• From: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>
• Date: Sun, 31 May 2009 06:34:35 -0400 (EDT)
• References: <gvq0aj$msg$1@smc.vnet.net>

Looks like a bug to me. For all u except -1 M[u] simplifies to 1 so
the output should be DiracDelta[t] not 1/(E^t*2)

Cheers -- Sjoerd

On May 30, 2:57 am, andrea.cor... at gmail.com wrote:
> OK, I give up on this one. Can anybody explain me the reason for these
> two different outputs?
>
> Many many many thanks in advance!
>
> Andrea
>
> In[304] psi[u_] := LaplaceTransform[Exp[-t], t, u]
>            M[u_] := u*psi[u]/(1 - psi[u])
>            InverseLaplaceTransform[M[u], u, t]
>            InverseLaplaceTransform[FullSimplify[M[u]], u, t]
>
> Out[306] 1/(E^t*2)
> Out[307] DiracDelta[t]