Re: Trignometric rules
- To: mathgroup at smc.vnet.net
- Subject: [mg118176] Re: Trignometric rules
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Fri, 15 Apr 2011 03:57:15 -0400 (EDT)
tt /. Cos[a_.*\[Phi]b + x_] -> 2 Sin[a*\[Phi]b] Sin[x]
Bob Hanlon
---- Chelly <chelly85086 at gmail.com> wrote:
=============
I have an expression as hsown below
tt = -4 k1^2 v^2 \[Epsilon]1^2 \[Epsilon]c^2 Cos[2 d1 + d2 + d3] -
2 k1 k2 u^2 \[Epsilon]1 Cos[d1 + d2 - \[Phi]b - \[Phi]r] +
2 k1^2 v^2 \[Epsilon]1^2 \[Epsilon]c^2 Cos[
2 d1 + d2 + d3 - \[Phi]b - \[Phi]r] +
2 k1^3 k2 v^2 \[Epsilon]1^3 \[Epsilon]c^2 Cos[
d1 + d3 + \[Phi]b + \[Phi]r] +
2 k1^2 u^2 \[Epsilon]1^2 Cos[2 d1 + d2 + d3 + \[Phi]b + \[Phi]r] -
2 k1^2 v^2 \[Epsilon]1^2 \[Epsilon]c^2 Cos[
2 d1 + d2 + d3 + \[Phi]b + \[Phi]r];
I'd like to replace any term containing Cos[+/- phib + x_] with 2 Sin [+/-phib] Sin[x]. How do I go about doing it.
Thanks
Chelly