Re: Bug in LaplaceTransform?

*To*: mathgroup at smc.vnet.net*Subject*: [mg97757] Re: Bug in LaplaceTransform?*From*: dh <dh at metrohm.com>*Date*: Fri, 20 Mar 2009 02:42:58 -0500 (EST)*References*: <gpsr23$mf1$1@smc.vnet.net>

Hi Wieland, sure that's wrong. But why? Consider: LaplaceTransform[1, t, a] ==> 1/a thats only correct if Re[a]>0, otherwise the transform is not defined. Mathematica seems to assumes, that the user only asks reasonable questions. Clearly "LaplaceTransform" is less smart than Integrate. Daniel Wieland Brendel wrote: > Dear reader, > how can it happen that Mathematica throws out -i for the Laplace > transform of one, > > LaplaceTransform[1, t, I] = -i? > > After all the Laplace transformation (with s = I) is defined as > > Integrate[Exp[-I t], {t, 0, Infinity}] > > and should be undefined. Am I wrong or is this a bug? > > Thanks for an answer! > Wieland >