SOLUTION: Write {{{ cos^2 (theta/8) - sin^2 (theta/8) }}} as a single trigonometric ratio.

Algebra ->  Trigonometry-basics -> SOLUTION: Write {{{ cos^2 (theta/8) - sin^2 (theta/8) }}} as a single trigonometric ratio.      Log On


   

Question 955346: Write +cos%5E2+%28theta%2F8%29+-+sin%5E2+%28theta%2F8%29+ as a single trigonometric ratio.
Answer by cobetta1(1) About Me  (Show Source):
You can put this solution on YOUR website!
Cos ^2(theta /8)-sin ^2( theta/8) "recall"( sin^2(theta)+cos^2(theta)=1) =Cos^2(theta /8)-(1-cos^2(theta /8))= cos^2(theta /8)+cos^2(theta /8)-1 = 2cos^2(theta /8)-1