Integrating DiracDelta to get UnitStep

*To*: mathgroup at smc.vnet.net*Subject*: [mg91238] Integrating DiracDelta to get UnitStep*From*: CRC <crobc at this-is-bogus.sbcglobal.net>*Date*: Mon, 11 Aug 2008 06:05:32 -0400 (EDT)

Hi: I am a bit confused by Mathematica 6.0.3 behavior. I expect that: In[n]:= Integrate[DiracDelta[x], {x, -\[Infinity], t}, Assumptions -> Im[t] == 0] Will produce: Out[n]= UnitStep[t] But instead it produces: Out[n]= 1 However, In[n+1]:= Plot[ Integrate[DiracDelta[x], {x, -\[Infinity], t}, Assumptions -> Im[t] == 0], {t, -2, 2} ] produces the expected plot of UnitStep[t]. Why doesn't the integration output the UnitStep function? Thanks for input. -- _____________________ CRC crobc at REMOVE-THIS.sbcglobal.net SuSE 10.3 Linux 2.6.22.17