Re: Assumptions for Trigonometry Inequalities

*To*: mathgroup at smc.vnet.net*Subject*: [mg71375] Re: Assumptions for Trigonometry Inequalities*From*: "dimitris" <dimmechan at yahoo.com>*Date*: Thu, 16 Nov 2006 00:53:05 -0500 (EST)*References*: <ejev72$1nt$1@smc.vnet.net>

Looks strange because Mathematica evaluates correctly e.g. Sin /@ Range[-Pi, 0, Pi/6] {0, -(1/2), -(Sqrt[3]/2), -1, -(Sqrt[3]/2), -(1/2), 0} Anyway, if you try Simplify[Sin[gamma] < 0, Pi < gamma < 2*Pi] True works fine. Martin Schoenecker wrote: > Hello, > > the Sin of a real number between zero and Pi should be positive, as > Simplify finds out, too. > > In[133]:= Simplify[Sin[gamma]>0,0<gamma<Pi] > Out[133]= True > > As well, the Sin of a number between -Pi and 0 is negative, but why > doesn't Simplify evaluate it? The Less implies that the variable is > real, I think, however stating it explicitly doesn't change the result. > > In[134]:= Simplify[Sin[gamma]<0,-Pi<gamma<0] > Out[134]= Sin[gamma]<0 > > Are there any hints on that? > Thank you, > Martin