Re: Trigonometric simplification

*To*: mathgroup at smc.vnet.net*Subject*: [mg68872] Re: Trigonometric simplification*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Mon, 21 Aug 2006 06:33:33 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <ecbnnc$r29$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

carlos at colorado.edu wrote: > As an intermediate result of some calculations I have > the expression > > r=Tan[a]^2/(Sec[a]^2)^(3/2) > > where a is real. How can I coerce Mathematica into > simplifying that to > > r=Cos[a]*Sin[a]^2 > > Both Simplify and FullSimplify with assumptions on a > fail to get the simpler form. Hi Carlos, Using TrigReduce before Simplify will do it: r = Tan[a]^2/(Sec[a]^2)^(3/2); Simplify[TrigReduce[r], Assumptions -> {a > 0, Sec[a] > 0}] --> Cos[a]*Sin[a]^2 Best regards, Jean-Marc