Re: Function argument

*To*: mathgroup at smc.vnet.net*Subject*: [mg66991] Re: Function argument*From*: Helen Read <hpr at together.net>*Date*: Tue, 6 Jun 2006 06:27:55 -0400 (EDT)*References*: <e60o3q$g5s$1@smc.vnet.net>*Reply-to*: read at math.uvm.edu*Sender*: owner-wri-mathgroup at wolfram.com

Bonny wrote: > I would like to define a function g that evaluates another function f at a > given value. That is, > > g[a, f[x]] := f[a] > > For example, I might want the function f[x]=ax^2+bx+c to be evaluated at x=1 > and get the result a+b+c. That is, > > g[1, ax^2+bx+c] should evaluate to a+b+c. Presumably you mean a x^2+b x + c, right? (Note the spaces between a and x^2, and between b and x). > Again, I might want the function f[x]=Sin[x] to be evaluated at x=pi and get You mean x=Pi, right? > the result 0. That is, > > g[pi, Sin[x]] should evaluate to 0. > > Is there a way to accomplish this in Mathematica? Any help would be > appreciated. g[a_,f_]:=f/.{x->a} will do what you want. -- Helen Read University of Vermont