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Expansion Coefficients in Multivariate Series Expansions?

• To: mathgroup at smc.vnet.net
• Subject: [mg26579] Expansion Coefficients in Multivariate Series Expansions?
• From: "A. E. Siegman" <siegman at stanford.edu>
• Date: Tue, 9 Jan 2001 01:51:53 -0500 (EST)
• Organization: Stanford University
• Sender: owner-wri-mathgroup at wolfram.com

Given an expression that is the sum of products of integer powers of 
three variables (say x,y,z) multiplied by numerical coefficients:

   f = c000 + c100 x + c010 y + c001 z + c110 x y + c211 x^2 y z + . . . 
   
where the  cijk's are all real numbers, and f may or may not be in 
Normal (or other) form, how do I find the coefficient of a particular 
term, e.g. c100 for the x term (*not*  c1000 + c110 y), or  ckmn for the 
x^k y^m z^n term?

Neither Coefficient nor SeriesCoefficient seems to do this -- and the  
SeriesCoefficient[expr, {n1,n2,n3,..}] syntax seems to be mentioned but 
neither explained or illustrated in the on-line Help.

Thanks, siegman at stanford.edu

• Follow-Ups:
  • Re: Expansion Coefficients in Multivariate Series Expansions?
    • From: Daniel Lichtblau <danl@wolfram.com>
  • Re: Expansion Coefficients in Multivariate Series Expansions?
    • From: Tomas Garza <tgarza01@prodigy.net.mx>