Question

1)arcsin(cos 22п/5)
2)sin(arccos(-2/5))

Answer 1

1) Cos 22π/5 = Сos(4π + 2π/5) = Cos2π/5
Sin(arcCos2π/5)= √(1-4π²/25) = √(25 - 4π²)/5
2) Sin(arcCos(-2/5))= √(1 + 2/25) = √27/5