Use a double-angle formula to rewrite the expression. cos2 x - 1 2Find all solutions of the equation in the interval [0, 2x). (Enter your answers as a comma-separated list. ) 8 sin X + 8 cos x = 0 2 X = 6' 6 XVerify the identity. 9 cos* x - 9 sin* x = 9 cos 2x 9 cos* x - 9 sin4 x = 9 (cos2 x - sin2 x) 3 cos (x) + sin2 x X = 9 cos (1) = 9 cos 2x