Solve for x State the general solution in radians without ap

Solve for x. State the general solution in radians without approximation. 4cos^2(x) - 4cos(x) + 1 = 0

Solution

4*cos^2 x – 4*cos x + 1 = 0

Let cos x = y =========> 4y^2 – 4y + 1 = 0

y = 0.5========> cos x = 0.5 =====> x = 60 degree, 300 degree

y = 0.5 ========> cos x = 0.5 =====> x = 60 degree, 300 degree