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>