[Date Index] [Thread Index] [Author Index]

Re: Simplify using custom function

• To: mathgroup at smc.vnet.net
• Subject: [mg47688] Re: [mg47676] Simplify using custom function
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Thu, 22 Apr 2004 02:38:32 -0400 (EDT)
• Reply-to: hanlonr at cox.net
• Sender: owner-wri-mathgroup at wolfram.com

expr=-1+2 x+2 E^x;

expr /. E^x -> f[x]-x  // Simplify

2 f(x)-1

However, f[x] cannot be defined or you will be back at expression.

Bob Hanlon

> 
> From: Jens <jens at tnntw10.tn.tudelft.nl>
To: mathgroup at smc.vnet.net
> Date: 2004/04/21 Wed AM 05:23:20 EDT
> To: mathgroup at smc.vnet.net
> Subject: [mg47688] [mg47676] Simplify using custom function
> 
> What I'm trying to achieve is to find a certain function in a more
> complicated expression:
> 
> example:    complicated expression: -1+2 x +2 e^x
> 	    function: f[x_]=x+e^x
> 
> 	    Mathematica should return: -1+2 f[x]
> 
> I've been looking at TransformationFunctions and FullSimplify, 
but did
> not succeed in defining a transformation function so far. How do I 
do
> that? (It's Mathematica 5.0)
> 
> Jens
> 
>