March 11th, 2011, 10:33 AM  #1 
Member Joined: Feb 2009 Posts: 54 Thanks: 0  Solve equation All Ive got so far is 
March 11th, 2011, 11:25 AM  #2 
Global Moderator Joined: Nov 2009 From: Northwest Arkansas Posts: 2,766 Thanks: 4  Re: Solve equation
So far, so good. Now replace sin^2(x) with 1  cos^2(x) in both places, and you should get a quadratic equation "in cos(x)". ie, if you sub U = cos(x), you'll be able to rewrite as aU^2 + bU + c = 0 and solve by usual methods. 
March 11th, 2011, 07:47 PM  #3 
Senior Member Joined: Apr 2007 Posts: 2,140 Thanks: 0 
Tank271, this should be very easy to solve if you know the trigonometric identities cos 2x = cos²x  sin²x and sin²x + cos²x = 1.


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