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Series problem

  • To: mathgroup at
  • Subject: [mg4084] Series problem
  • From: f85-tno at (Tommy Nordgren)
  • Date: Fri, 31 May 1996 01:36:00 -0400
  • Organization: Royal Institute of Technology, Stockholm, Sweden
  • Sender: owner-wri-mathgroup at

	I want to expand the Cosine only in the expression:
Cos[b x] Exp[-x^2]/(k^2+x^2) into a taylor series around 0.
Computing the series in terms of x don't work, because the exponetial and
the divisor will be expanded as well, when the series of the Cosine is 
multiplied by the other factors.
Making the series expansion in terms of b don't work, because Mathematica 
can't integrate the resulting series expansion in terms of x.
Are there any way to handle this except by introducing a new representation
for function series. 
(The problem I'm currently interested in is finding a series for the function
f[b_,k_] = Integrate[Cos[b x] Exp[-x^2]/(k^2+x^2),{x,-Infinity,Infinity}],
which is valid for small b)
Tommy Nordgren                    "Home is not where you are born,
Royal Institute of Technology      but where your heart finds peace."
Stockholm                         Tommy Nordgren - The dying old crone
f85-tno at         						  


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