Solve for θ, to the nearest degree, in the interval 0 0 ≤ θ ≤ 360 4cos2 θ = 1

Answer 1

4cos(2theta)=1

cos(2theta)= 1/4

arccos(cos(2theta)= arccos(1/4)

2theta = 1.318 rads

theta = 1.318/2

theta = 0.6595 rads or 37.80 degrees