it says to solve for cos pi/3 using a double angle identity.

I dont understand whats wrong.

I do

cos(pi/3)

cos(2(pi/6)) This is where im stuck, what do you do when you have a squared sin/ cos, I know sin of pi/6 = 1/2 and cos = root 3 over 2 so dont you just square those so

3/4 times 1/4?

that gives the wrong answer though its supposed to be 1/2

thanks.