SOLUTION: Can someone please check my work? The question says write the expression as sine, cosine or tan of a double angle and find exact value. cos^2 60 -sin ^2 60 I got Sin (1

Algebra ->  Trigonometry-basics -> SOLUTION: Can someone please check my work? The question says write the expression as sine, cosine or tan of a double angle and find exact value. cos^2 60 -sin ^2 60 I got Sin (1      Log On


   

Question 919589: Can someone please check my work?
The question says write the expression as sine, cosine or tan of a double angle and find exact value.
cos^2 60 -sin ^2 60
I got
Sin (120) which is sqrt 3 / 2.
Are you just supposed to add the two values?
thanks

Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
The question says write the expression as sine, cosine or tan of a double angle and find exact value.
cos^2 60 -sin ^2 60
Identity: cos(2x)=cos^2(x)-sin^2(x)
cos^2 60 -sin ^2 60=cos(2*60)=cos(120˚)