Re: assigning functions
- To: mathgroup at smc.vnet.net
- Subject: [mg56238] Re: [mg56204] assigning functions
- From: "Christoph Lhotka" <lhotka at astro.univie.ac.at>
- Date: Wed, 20 Apr 2005 05:30:13 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi! In[1]:= f[x_]:= x^2 In[2]:=fprime[x0_]:=D[f[x],x]/.x->x0 In[3]:= f[8] Out[3]:= 64 In[4]:= fprime[8] Out[4]:= 16 with kind regards... On Tue, 19 Apr 2005 04:55:01 -0400 (EDT) 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 > -- Christoph Lhotka -- University of Vienna Institute for Astronomy Tuerkenschanzstr. 17 1180 Vienna, Austria fon. +43.1.4277.518.41 mail. lhotka at astro.univie.ac.at