Re: Built-In fuctions redefined---How?
- To: mathgroup at smc.vnet.net
- Subject: [mg62632] Re: [mg62589] Built-In fuctions redefined---How?
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Wed, 30 Nov 2005 00:06:11 -0500 (EST)
- Reply-to: hanlonr at cox.net
- Sender: owner-wri-mathgroup at wolfram.com
One approach that only affects the output.
$Post=(#/.
{Sin[x_Symbol]/;StringLength[ToString[x]]==1:>
ToExpression["s"<>ToString[x]],
Cos[x_Symbol]/;StringLength[ToString[x]]==1:>
ToExpression["c"<>ToString[x]]}&);
expr=Sin[x]^2+Cos[x]^2+Cos[y]-Sin[z]
cx^2 + sx^2 + cy - sz
expr//Simplify
cy - sz + 1
Bob Hanlon
>
> From: Virgil Stokes <virgil.stokes at it.uu.se>
To: mathgroup at smc.vnet.net
> Date: 2005/11/29 Tue AM 04:44:26 EST
> Subject: [mg62632] [mg62589] Built-In fuctions redefined---How?
>
> How can I introduce the following definitions:
>
> cx for Cos[x]
> sx for Sin[x]
>
> where, the argument x, will always be a single symbol, and then still be
> able to use the trigonometric identities associated with Sin, Cos; e.g.,
>
> cx^2 + sx^2 = 1
>
> Note, this is not c x (3 symbol expression); but, cx (2 symbol
> expression).
> Why? Because I have some rather large matrices with many elements that
> contain expressions in Cos and Sin terms that make printing and
> displaying messy and using the MatrixForm can give truncation in the
> printed output.
>
> --V. Stokes
>
>
>
>
>