Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1998
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1998

[Date Index] [Thread Index] [Author Index]

Search the Archive

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.
>
>



  • Prev by Date: Re: Levy Distribution
  • Next by Date: Modifying the Mathematica menus
  • Previous by thread: Bug in Calculus`DiracDelta`
  • Next by thread: Re: Bug in Calculus`DiracDelta`