Re: Trigonometric simplification

*To*: mathgroup at smc.vnet.net*Subject*: [mg68890] Re: Trigonometric simplification*From*: "Dana DeLouis" <dana.del at gmail.com>*Date*: Tue, 22 Aug 2006 05:20:29 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

> r=Tan[a]^2/(Sec[a]^2)^(3/2) > simplifying that to > r=Cos[a]*Sin[a]^2 r = Tan[a]^2/(Sec[a]^2)^(3/2); Hi. Just one of a few ways. With a Sqrt on Sec[a], try to find values of 'a where Sec[a] is positive. Since I've forgotten what they are... Plot[Sec[a], {a, -Pi, Pi}, Ticks -> {Range[-Pi, Pi, Pi/4], Automatic}]; Therefore: Assuming[{-Pi/2 < a < Pi/2}, Simplify[r]] Cos[a]*Sin[a]^2 -- HTH. :>) Dana DeLouis Windows XP, Mathematica 5.2 <carlos at colorado.edu> wrote in message news:ecbnnc$r29$1 at smc.vnet.net... > 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. >