sec(3x) = 2
sec (3x) = 2
This happens where cos (3x) = 1/2
So 3x = pi/3 + 2 pi *n and 3x = 5pi / 3 + 2pi*n where n is an integer
Dividing both sides by 3, we have that
x = pi/9 + (2/3)pi*n and x = 5pi/ 9 + (2/3)pi*n where n is an integer
