Re: Bug in Calculus`DiracDelta`

*To*: mathgroup at smc.vnet.net*Subject*: [mg14801] Re: Bug in Calculus`DiracDelta`*From*: "M. Rommel" <rommel at bc.edu>*Date*: Wed, 18 Nov 1998 01:29:01 -0500*Organization*: UltraNet Communications , an RCN Company http://www.ultranet.com/*References*: <72je71$3f9@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Let me add that the correct solution is Integrate[DiracDelta[Cos[phi]],{phi,Pi,2Pi}]=1 You may take the Cos out of the DiracDelta, then you have Integrate[DiracDelta[phi -3Pi/2]/Abs[Sin[3Pi/2]],{phi,Pi,2Pi}]=1 Apparently the DiracDelta package fails in that regard M. Rommel wrote in message <72je71$3f9 at smc.vnet.net>... >I know normally "it's the user, stupid!" but this one seems real. > >In[1]:= <<Calculus`DiracDelta` > >In[2]:= Integrate[DiracDelta[Cos[x]],{x,0,\[Pi]}] > >Out[2]= 1 > >That's what I agree with but the next line I cannot: > >In[3]:= Integrate[DiracDelta[Cos[x]],{x,\[Pi],2\[Pi]}] > >Out[3]= 0 > >Any comments/insights/etc. pp.? > >Cheers, Martin. > >