Re: Trigonometric simplification

*To*: mathgroup at smc.vnet.net*Subject*: [mg68904] Re: Trigonometric simplification*From*: Paul Abbott <paul at physics.uwa.edu.au>*Date*: Tue, 22 Aug 2006 05:20:55 -0400 (EDT)*Organization*: The University of Western Australia*References*: <ecbnnc$r29$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <ecbnnc$r29$1 at smc.vnet.net>, 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 It doesn't simplify because it is not true in general for a real. However, Simplify[Tan[a]^2/(Sec[a]^2)^(3/2), -(Pi/2) < a < Pi/2] Cos[a] Sin[a]^2 and Simplify[Tan[a]^2/(Sec[a]^2)^(3/2), Pi/2 < a < 3 Pi/2] -(Cos[a] Sin[a]^2) Cheers, Paul _______________________________________________________________________ Paul Abbott Phone: 61 8 6488 2734 School of Physics, M013 Fax: +61 8 6488 1014 The University of Western Australia (CRICOS Provider No 00126G) AUSTRALIA http://physics.uwa.edu.au/~paul