Re: assigning functions
- To: mathgroup at smc.vnet.net
- Subject: [mg56223] Re: [mg56204] assigning functions
- From: yehuda ben-shimol <bsyehuda at gmail.com>
- Date: Wed, 20 Apr 2005 05:29:53 -0400 (EDT)
- References: <200504190855.EAA02540@smc.vnet.net>
- Reply-to: yehuda ben-shimol <bsyehuda at gmail.com>
- Sender: owner-wri-mathgroup at wolfram.com
All you need is to assign the value of x AFTER applying the function, so do as follows fprime[x]/.x->2 Or define the function differently such as fprime1[f_,x_]:=Module[{y},D[f[y],y]/.y->x] and then call it with fprime1[f,2] and get the desired results. Please note that I modified fprime1 a little bit so it would be more general and can be applied for other functions and not only on the globally defined f[x_]:=x^2 as you did good luck yehuda On 4/19/05, juejung <juejung at indiana.edu> wrote: > dear all, > > i would like to do the following. > assign a function: > f[x_] := x^2; > > take its derivate: > D[f[x], x] > > and assign the result of this to a new function, like fprime[x]: > fprime[x_] := D[f[x], x] > > unfortunately that doesn't work. > when i try to evaluate fprime[2] i get an error message. > > can somebody please help, this haunts me for a while now. > > thanks and all the best > > juergen > >
- References:
- assigning functions
- From: juejung <juejung@indiana.edu>
- assigning functions