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Re: Sin*Cos + Log

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  • Subject: [mg113249] Re: Sin*Cos + Log
  • From: Sam Takoy <sam.takoy at>
  • Date: Wed, 20 Oct 2010 04:09:41 -0400 (EDT)

Dear Bob,


My hope is that I can define f without mentioning the arguments, as in

f = Sin*Cos + Log

It doesn't make much difference in this case, but in my case I have something 
along the lines of

f[t_, x_, y_, z_] = g[t, x, y, z]*h[t, x, y, z] + Derivative[0, 0, 1, 0][h][t, 
x, y, z]   etc

and I'd like to say

f = g*h + Derivative[0, 0, 1, 0][h]

skipping the arguments.

Is that possible?



From: Bob Hanlon <hanlonr at>
To: Sam Takoy <sam.takoy at>; mathgroup at
Sent: Tue, October 19, 2010 7:20:45 AM
Subject: [mg113249] Re: [mg113215] Sin*Cos + Log

f[x_?NumericQ] := Sin[x]*Cos[x] + Log[x]

f /@ {x, 2, 2.}

{f[x], Log[2] + Cos[2] Sin[2], 0.314746}

x /: NumericQ[x] = True;

f /@ {x, y}

{Log[x] + Cos[x] Sin[x], f[y]}

Bob Hanlon

---- Sam Takoy <sam.takoy at> wrote: 


I'm working on a project that involves manipulating lots of functions. 
It would be much easier if I could manipulate functions without 
evaluating them and then evaluate them at the end. To this end, is there 
a way to endow

f = Sin*Cos + Log

with meaning and then somehow evaluate


Many thanks in advance,


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