How do you solve 4 cosine squared theta equals 1?

Answer 1

4*cos2(theta) = 1

cos2(theta) = 1/4

cos(theta) = sqrt(1/4) = ±1/2

Now cos(theta) = 1/2 =>

theta = 60 + 360k

or

theta = 300 + 360k

while

Now cos(theta) = -1/2 =>

theta = 120 + 360k

or

theta = 240 + 360k

where k is an integer.