sin[x] * cos[pi/6] - cos[x] * sin[pi/6] <= 1/2sin(x - π/6) ≤ - 1/2- π - arcsin(-1/2) ≤ (x - π/6) ≤ arcsin(-1/2) + 2πn, n∈Z- π + π/6 ≤ ( x - π/6) ≤ - π/6 + 2πn, n∈Z- 5π/6 ≤ ( x - π/6) ≤ - π/6 + 2πn, n∈Z- 5π/6 + π/6 ≤ x ≤ - π/6 + π/6 + 2πn, n∈Z-4 π/6 ≤ x ≤ 0 + 2πn, n∈Z- 2π/3 ≤ x ≤ 2πn, n∈Z