Solving a Sum

*To*: mathgroup at smc.vnet.net*Subject*: [mg89875] Solving a Sum*From*: Igor <pischek at gmx.net>*Date*: Mon, 23 Jun 2008 02:49:17 -0400 (EDT)

Hi All! I just started using mathematica for university and encounter the following issue which I am not able to figure out myself. I have to equations: eq1:=Sum[(Subscript[z,t]+Subscript[c,t]*Subscript[c,0])*q^(-t),{t,1,T}]==Subscript[z,0]+Sum[Subscript[z,t]*q^(-t),{t,1,T}] and eq2:=Subscript[z,t]==Subscript[s,t]*u I would like to solve these equations for c_t but get the following error message when using the Solve command as follows: Solve[{eq1, eq2}, Subscript[c, t]] Solve::tdep: The equations appear to involve the variables to be solved for in an essentially non-algebraic way. >> How can I solve this problem? Thanks a lot! Igor