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From: steviep2 <ssplotkin@gmail.com>
Newsgroups: comp.soft-sys.math.mathematica
Subject: Using FindRoot with free parameters
Date: Sat, 12 Apr 2014 09:16:12 +0000 (UTC)
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Hi,
I want to define a function of 2 parameters that uses FindRoot. I.e. I have a known but complicated function f[n_,x_] = "complicated function of (n,x)". I want to find the value of x where f[n,x] == alpha, and I want to call this a function xf[alpha_,n_].

So my attempts (this is non-working code) looks something like this: 

xf[alpha_, n_] =  Function[{x}, x /. FindRoot[f[n,x] - alpha, {x, 2}]]

or
xf[alpha_, n_] =  Function[x /. FindRoot[f[n, x] - alpha, {x, 2}]][alpha, n]

It seems this is a pretty simple question-- basically using FindRoot but holding off on substituting in the parameters until later. Is there a simple solution?

Thanks, 
StevieP