Вычислите: cos(2arcsin(1/4))

Question

Вычислите: cos(2arcsin(1/4))

Answer 1

cos(2*arcsin(1/4)) = 1 - 2 * sin²(arcsin 1/4) = 1 - 2 * (1/4)² = 1 - 1/8 = 7/8 = 0,875