       Re: Root search on results of minimization with free

• To: mathgroup at smc.vnet.net
• Subject: [mg114796] Re: Root search on results of minimization with free
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Fri, 17 Dec 2010 03:29:55 -0500 (EST)

```example[c_, x_] = x^2 + c/2;

f[c_?NumericQ] := NMinimize[example[c, x], x][];

FindRoot[f[c] == 0, {c, 14}]

{c -> 0.}

Bob Hanlon

---- "Philipp Wei=C3=9Fgraeber" <weissgraeber at fsm.tu-darmstadt.de> wrote:

=============
Hello all!

I have a function f which is for example the result of a minimization with
respect to x. It still depends on a parameter c. Now I want to find the root
(or minima or whatever) of the the function f with respect to c.
This seems does not work.
I always get the errors "NMinimize::nnum: Function value is not a number"
resp. "FindRoot::nlnum: The function value is not a list of numbers"

Example:
example[c_, x_] = x^2 + c/2;
f[c_] := NMinimize[example[c, x], x][];
FindRoot[f[c] == 0, {c, 14}]

How can I implement this?
My original problem is of course of more complex nature, but it boils down to
this.

Thank you

Philipp

```

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