How can I simplify a series with some multiplicative factor?

*To*: mathgroup at smc.vnet.net*Subject*: [mg55662] How can I simplify a series with some multiplicative factor?*From*: Zhou Jiang <jiangzhou_yz at yahoo.com>*Date*: Fri, 1 Apr 2005 05:37:09 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, My colleagues, I want Mathematica to simplify the following expression x^2 Sum[C[n] x^n ,{n,0,Infinity}] I wrote Simplify[%] to do the job but the expression is not changed at all. How can I get the result something like C[n] x^(n+2), i.e., I hope Mathematica can move the x^2 term in the summation operator. Can anyone give me some idea? Thank you very much. Daxin Shi