Find all solutions of the equation Give exact values in radi

Find all solutions of the equation. Give exact values, in radians. 2sin^2 theta = 5 cos theta-1

2sin²(theta) = 5cos(theta) - 1

2(1 - cos²(theta)) = 5cos(theta) - 1

2cos²(theta) + 5cos(theta) - 3 = 0

cos(theta) = 0.5 (possible) or cos(theta) = -3 (not possible)

for theta belongs to [0,2pi)

theta = pi/3 , 5pi/3