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 > > > > >