Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2005
*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 2005

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

Search the Archive

Re: Re: (x-y) DiracDelta[x-y] does not simplify to 0

  • To: mathgroup at smc.vnet.net
  • Subject: [mg56376] Re: [mg56297] Re: (x-y) DiracDelta[x-y] does not simplify to 0
  • From: Alain Cochard <alain at geophysik.uni-muenchen.de>
  • Date: Sat, 23 Apr 2005 01:16:08 -0400 (EDT)
  • References: <4FDA877403669E48A2CB7F1122A7948045C78F@dassne02.da.gei>
  • Reply-to: alain at geophysik.uni-muenchen.de
  • Sender: owner-wri-mathgroup at wolfram.com

Wolf, Hartmut writes:

 > In[14]:= f[x_,y_] := (1 + x + y + x^2)/(x - y)
 > 
 > In[15]:= Integrate[f[x,y]*(x - y)DiracDelta[x - y], {x, -Infinity,
 > Infinity}]
 > Out[15]= (1 + y)^2

OK, with this example I realize that Andrzej and Yehuda were probably
correct from the start, since with my simplification outside the
integral, and if not too careful, I might have deduced that this would
give 0.

Thanks again everybody,
Alain


  • Prev by Date: Re: A bug in Integrate ?
  • Next by Date: Re: Can I make permanent font settings in Mathematica 5
  • Previous by thread: Re: Re: (x-y) DiracDelta[x-y] does not simplify to 0
  • Next by thread: Re: assigning functions