Re: Solving periodic functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg74969] Re: [mg74935] Solving periodic functions*From*: János <janos.lobb at yale.edu>*Date*: Fri, 13 Apr 2007 02:01:20 -0400 (EDT)*References*: <200704120846.EAA24338@smc.vnet.net>

On Apr 12, 2007, at 4:46 AM, David Rees wrote: > This is probably totally elementary, but I'm stumped nonetheless. > > Anyway, in Mathematica, how do I solve an equation with multiple > periodic > functions within a given function domain bound? > > i.e. How would I find all values of x given 6Cos[x]-5Cos[x] = 0 = where > 0<x<=2Pi ? > > thanks > > Me as a newbie, I would start with Reduce. In[2]:= Reduce[{6*Cos[x] - 5*Sin[x] == 0, Inequality[0, Less, x, LessEqual, 2*Pi]}, x] Out[2]= x == 2*Pi + 2*ArcTan[ (1/6)*(-5 - Sqrt[ 61])] || x == 2*ArcTan[(1/6)* (-5 + Sqrt[61])] J=E1nos ---------------------------------------------- Trying to argue with a politician is like lifting up the head of a corpse. (S. Lem: His Master Voice)

**References**:**Solving periodic functions***From:*"David Rees" <w3bdevilREMOVE@THISw3bdevil.com>