Question

cos(x/3)cos(x/3)=1/2(1+cos(2x/3))

Answer 1

This follows from the half-angle identity for cosine.

$\cos^2\theta=\dfrac{1+\cos2\theta}2$

Answer 2

Answer:

it's true, don't have a step by step explanation just did it on my test.

Step-by-step explanation: