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Re: Bug in Calculus`DiracDelta`

  • To: mathgroup at
  • Subject: [mg14801] Re: Bug in Calculus`DiracDelta`
  • From: "M. Rommel" <rommel at>
  • Date: Wed, 18 Nov 1998 01:29:01 -0500
  • Organization: UltraNet Communications , an RCN Company
  • References: <72je71$>
  • Sender: owner-wri-mathgroup at

Let me add that the correct solution is


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>...
>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.

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