Write the expression in terms of sin x and cos x cos^2 (2x) - sin 2x

Hi! So in this you use the Pythagorean Theorem. In triangle CBD, you would do 6^2 + 4.2 ^2 = y ^2. You take the square root of that answer to get the dumber. Then, you would have 2 sides for triangle CAD, so you could just do it again, getting the answer for X. I hope that helps. I don’t know if that is how you are learning it or not, but that is a way to solve.