Evaluate each of the following expressions without the aid o

Evaluate each of the following expressions without the aid of a calculate sin 660 degree cos^-1(-Squareroot 3/2) sin (cos^-1(5/8))

Solution

a) sin2x = 2sinx*cosx

sin660 = sin(2*330) = 2sin330cos330 = 2*-3/2*1/2 = -23/4 = -3/2

b) cos^-1(-3/2) = 150 degree

c) sin(cos^-1(5/8)) = sin(51.3178) = 0.7806