Question

4 cos² theta+ 4 cos theta= 1

Answer 1

Explanation:

Let 'x' = cos Φ

then you have

4x^2 + 4x -1 = 0 now use quadratic formula to find

x = .207107 and -1.20711 ( throw out.....cos cannot be less than -1 )

cos Φ = .207107

then

arcos ( .207107 ) =Φ = 78.05 degrees and 281.95 degrees