How to use SeriesCoefficient to define new functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg122743] How to use SeriesCoefficient to define new functions*From*: Xiaojun <tigertooth4 at gmail.com>*Date*: Tue, 8 Nov 2011 07:17:21 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Hi, I want to define new functions from the =EB-expansion of an exponential function as follows: SchurGenerator := Normal[Series[ Exp[x1*=EB + x2*=EB^2 + x3*=EB^3], {=EB, 0, 3}]]. Each coefficient may define a function of x1, x2, and x3, which I think should be expressed as, for example: p2[x1_, x2_, x3_] := SeriesCoefficient[SchurGenerator, {=EB, 0, 2}]. However, it doesn't seem to work. Since the expected output of p2[y1,y2,y3] should be y1^2/2 + y2. But the real output is still x1^2/2 + x2. How to define new functions from the expansion coefficients? I appreciate your help ! -- Best wishes, Liu Xiaojun