Question 7 Not yet cos(utv) = cos(u) cos(v) -sin(u) sin(v) X answered Points out of 3.00 Flag sin ( 2u) = 2 sin(u) cos(u) question cos (21) = 2 cos (1) -1 Use multiple-angle formulas and sum-and-difference formula above to rewrite cos3x in terms of only cos(x). You should get down to two terms in your final answer! Hint: Start by rewriting cos(3x) into cos(2x + X)