Find all solutions of the equation cos x2 sin x 1 0 The an

Find all solutions of the equation cos x(2 sin x + 1) = 0. The answer is A + kpi, B + 2kpi and C + 2kpi where k is any integer where 0

cosx(2sinx+1) =0

cosx =0

x = pi/2, 3pi/2

General solution : A = pi/2 +k*pi

2sinx +1 =0

sinx = -1/2

x= pi+pi/6 , 2pi -pi/6 = 7pi/6 , 11pi/6

General solution : B = 2k*pi +7pi/6

C = 2k*pi +11pi/6

Now A = pi/2

B = 7pi/6

C = 11pi/6