Please help me with this question thank you An equation is g

Please help me with this question thank you.

An equation is given. (Enter your answers as a comma-separated list. Round terms to three decimal places where appropriate If there is no solution, enter NO SOLUTION.) - 2/Squareroot3 cos 3theta= 1 Find all solutions of the equation. Find the solutions in the interval [0, 2pi).

Solution

cos(3theta) = -sqrt(3)/2

3(theta) = 5pi/6 +2(pi)n , 7pi/6+2(pi)n, 5pi/6 -2(pi)n , 7pi/6-2(pi)n

a)theta = 5pi/18 +2(pi)n/3, 7pi/18+2(pi)n/3, 5pi/18 -2(pi)n/3 , 7pi/18-2(pi)n/3

b)theta = 5pi/18,7pi/18