Re: nested findroot

*To*: mathgroup at smc.vnet.net*Subject*: [mg122802] Re: nested findroot*From*: Ray Koopman <koopman at sfu.ca>*Date*: Fri, 11 Nov 2011 04:53:05 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <j9genv$p2n$1@smc.vnet.net>

On Nov 10, 4:06 am, Anna McCuan <anna.mcc... at gmail.com> wrote: > I'm getting an error finding a root using functions which are defined > using findroot. This happens in spite of the fact that I can graph > the function and see clearly that there is an easy to find root. > Does anyone know how to execute this root search successfully? > > The file is posted publicly at > http://www.math.gatech.edu/~mccuan/temp/problem.nb Change the definitions of f and g so that they apply only when the argument is numeric: f[w_?NumericQ] := ... g[w_?NumericQ] := ... FindRoot[g[soln] - 9 f[soln] == 0, {soln, .13}] {soln -> 0.131216}