June 15th, 2014, 02:07 AM  #1 
Senior Member Joined: Nov 2013 Posts: 434 Thanks: 8  theta 
June 15th, 2014, 10:49 AM  #2 
Senior Member Joined: Feb 2010 Posts: 702 Thanks: 137 
Chasing angles around the picture quickly yields that $\displaystyle \angle PCM = \theta$. Thus $\displaystyle PC=PM=BC$. Without loss of generality let $\displaystyle AM=1$. Then $\displaystyle MC=1$, and $\displaystyle BC=PC=PM=2\sin \theta$ Writing the law of cosines on $\displaystyle \triangle PMC$ gives you that $\displaystyle \sin 2\theta=1/2$ and $\displaystyle \theta=15$. 

Tags 
theta 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
prove : A X B = ab sin (theta)  MATHEMATICIAN  Algebra  12  January 4th, 2015 03:19 PM 
if sin(theta)= .1234 find (theta) in [4pi,pi]  mauro125  Algebra  3  February 22nd, 2014 05:57 PM 
d²y/dx² and theta angle  Jhenrique  Calculus  1  November 23rd, 2013 11:02 AM 
Eliminating theta???  MadSoulz  Algebra  6  September 10th, 2012 09:26 PM 
[P*cos (theta)]  [A*sin(theta)] = 0, thus tan(theta)=(P/A)?  FelisCanisOfCadog  Algebra  4  March 6th, 2009 09:05 PM 