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Re: Trignometric rules

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tt /. Cos[a_.*\[Phi]b + x_] -> 2 Sin[a*\[Phi]b] Sin[x]


Bob Hanlon

---- Chelly <chelly85086@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

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Re: Trignometric rules Bob Hanlon <hanlonr@cox.net> - 2011-04-15 07:57 +0000

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