Question 925757
2 cos 2θ − 1 = 0 
cos x = 1/2
x = π/3 , 5π/3  (See Below)
2θ = x
θ = x/2
θ = π/6 + 2kπ , 5π/6 +  2kπ
.......
(b) Find the solutions in the interval [0, 2π).
θ = π/6 , 5π/6 
..........
(cosx, sinx) Summary Unit Circle
*[illustration wheel_smaller.jpg].