Simplify for ca^2+sa^2==1

*To*: mathgroup at smc.vnet.net*Subject*: [mg26339] Simplify for ca^2+sa^2==1*From*: Adalbert Hanssen <hanssen at Zeiss.de>*Date*: Tue, 12 Dec 2000 02:54:50 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, MathGroup, in a lengthy expression, I know, a lot of simplification can be done, if Simplify and the like would take into account that for varaibles ca and sa ca^2+sa^2==1 I know, that I can set ca=Sqrt[1-sa^2] and deal with the branch cut by hand. The bad thing is, that these ca^2 and sa^2 are expanded out in lenghty subexpressions involving lots of other symbols. So far, I have found no way (but would be glad, if someone could advise me one), to factor out (ca^2+sa^2). Unfortunately, there are also terms, where (1+ca^2+sa^2) or (2*ca^2+2*sa^2) can be factored out, also others with (-ca^2-sa^2) and so on. Any general tip, how to best cope with such algebraic manipulations? kind regards Dipl.-Math. Adalbert Hanszen

**Follow-Ups**:**Re: Simplify for ca^2+sa^2==1***From:*"Carl K. Woll" <carlw@u.washington.edu>