FindRoot with algebraic expressions

*To*: mathgroup at smc.vnet.net*Subject*: [mg122808] FindRoot with algebraic expressions*From*: Mirko <dashiell at web.de>*Date*: Fri, 11 Nov 2011 04:54:10 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Hi, I was wondering how FindRoot works when trying to use a algebraic initial point. I.e.: FindRoot[h[theta]==0,{theta[m], ???}] where h is function of theta, for example: h[theta_]=1/(1-m)*theta[m] (notice that this is for a given m). What should I use as a starting point? If I just use 1 as a starting point, it returns a mistake. However, I could use the solution of a first step approximation, but it doesn't work as well. Here is what I mean: t0=Solve[h1[theta]==0,theta[m]] (where h1 is a different function, similar to h). Plugging t0 into ??? returns a mistake as well. This is probably due to the format? Although, even if I use theta[m]/.Solve[h1[theta]==0,theta[m]] and plugging theta[m] into ??? gives me a mistake.