Re: Simplifying algebraic expr: howto?
- To: mathgroup@smc.vnet.net
- Subject: [mg11404] Re: Simplifying algebraic expr: howto?
- From: Allan Hayes <hay@haystack.demon.co.uk>
- Date: Sun, 8 Mar 1998 20:13:24 -0500
- References: <6dqqf0$rk0@smc.vnet.net>
Daniel G. Hyams wrote:
> I have an expression (for example):
>
> u*(nx*u + ny*v) ---- (1)
>
> and a definition:
>
> theta = nx*u+ny*v
>
> How do I get mathematica to simplify the expression (1) such that it
> returns:
>
> u*theta ?
>
Daniel,
One way is
In[1]:=
u*(nx*u + ny*v)/.{nx*u+ny*v->theta}
Out[1]=
theta u
You might want to accumulate several rules in a list
myRules = {nx*u+ny*v->thet, ....}
and use them all together
expr/.myRules
and even repeatedly
expr//.myRules
--
Allan Hayes
Training and Consulting
Leicester, UK
hay@haystack.demon.co.uk
http://www.haystack.demon.co.uk
voice: +44 (0)116 271 4198
fax: +44 (0)116 271 8642