Solve the equation on the interval 0 lessthanorequalto theta

Solve the equation on the interval 0 lessthanorequalto theta 2 pi. 2Squareroot 2 cos theta + 3 = 5 What are the solutions in the interval 0 lessthanorequalto theta

Solution

2 sqrt2 cos theta + 3=5

2 sqrt 2 cos theta=2

sqrt 2 cos theta =1

cos theta =1/sqrt2

theta=cos^-1(1/sqrt 2)

theta = pi/4 , 7pi/4

We need to select option A and the solution set is (pi/4 , 7pi/4)