Re: Function argument
- To: mathgroup at smc.vnet.net
- Subject: [mg66992] Re: Function argument
- From: Bill Rowe <readnewsciv at earthlink.net>
- Date: Tue, 6 Jun 2006 06:28:07 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
On 6/5/06 at 3:47 AM, Banerjee at cse.ohio-state.edu (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. Note in Mathematica ax is distinctly different from a x or a*x. So, unless g is written in an unusual way, g[1,ax^2+bx+c] will not evaluate to a+b+c But it is quite easy to create a function that will return what you want given the arguments 1 and a*x^2+b*x+c. For example, In[1]:= g[a_, f_] := f /. x -> a In[2]:= g[1,a x^2+b x+c] Out[2]= a+b+c >Again, I might want the function f[x]=Sin[x] to be evaluated at x=pi >and get the result 0. That is, >g[pi, Sin[x]] should evaluate to 0. In[3]:= g[Pi,Sin[x]] Out[3]= 0 Note, the definition I've used for g assumes x as the independent variable. Also, I wonder why you want such a function since it as easy (if not easier) to write In[4]:= a x^2 + b x + c /. x -> 1 Out[4]= a+b+c instead of g[1,a x^2+b x+c] -- To reply via email subtract one hundred and four