SOLUTION: coul you help me about this?!? Prove the identity {{{Cos^2(2y)-4Sin^2(y)Cos^2(y)=Cos(4y)}}}

Question 203947: coul you help me about this?!?
Prove the identity

Answer by Edwin McCravy(20065) (Show Source): You can put this solution on YOUR website!



        

Work with the right side:
                           

                          

                          

                          
               
                          
    
                           

                          

Edwin

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