An equation is given Enter your answers as a commaseparate 2

An equation is given. (Enter your answers as a comma-separate -2/squareroot cos(3 theta) = 1 Find all solutions of the equation. theta = Find the solutions in the interval [0, 2pi). theta =

Solution

a) (-2/3)*cos(3) = 1

cos(3) = -3/2

3 = (5/6 + 2*k), (7/6 + 2*k)

= (5/18 + 2*k/3), (7/18 + 2*k/3)

b) [0,2]

cos 3=1/(-2/3)=-3/2
3=7/6 and 11/6 in quadrants III and IV where cos<0
=7/18 and 11/18