precalc math problem

Question

Solve the equation for exact solutions over the interval

[0,360°).

sec(3θ)=−1

Answer 1

sec3T=-1

1/cos3T=-1

cos3T=-1

3T=pi, 3pi or 5pi

T= pi/3, pi or 5pi/3

or

= 60, 180 or 300 degrees = Theta

sec3(60) = sec180 = -1

sec3(180) = sec540 = sec(540-360) = sec180=-1

sec3(300) = sec900=sec(900-2(360))= sec(900-720) = sec180 =-1