Re: Expansion Coefficients in Multivariable Series Expansions?

*To*: mathgroup at smc.vnet.net*Subject*: [mg26595] Re: Expansion Coefficients in Multivariable Series Expansions?*From*: "Ersek, Ted R" <ErsekTR at navair.navy.mil>*Date*: Thu, 11 Jan 2001 10:39:09 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

A. E. Siegaman basically had a polynomial in several variables say (x,y,z) and as I understand it wanted the coefficient of (x) as returned by the following. In[1]:= poly = 3x + Pi x - 2x y^2 + x z^3; Part[CoefficientList[poly,{x,y,z}],2,1,1] Out[1]= 3 + Pi --------------- Then if poly is a polynomial in (w,u,v,x,y,z) you can get the coefficient of x by using the following. Part[ CoefficientList[poly, {w,u,v,x,y,z}], 1,1,1,,2,1,1] --------------- Lookup CoefficientList on my website http://www.verbeia.com/mathematica/tips/Tricks.html for a detailed explanation of this function. --------------- Regards, Ted Ersek