cos x = -√3/2

The equation cos x = -√3/2 has solutions in the second and third quadrants. The reference angle for which cos(θ) = √3/2 is π/6. Therefore, the principal values for x are π - π/6 = 5π/6 and π + π/6 = 7π/6. The general solution is given by x = ± 5π/6 + 2πn, where n is an integer.