sin²(x/6) - cos²(x/6) = 1/2
-cos(2*x/6) = 1/2
cos(x/3) = -1/2
x/3 = ±2π/3 + 2πn, n ∈ Z
x = ±2π + 6πn , n ∈ Z
sin²(x/6) - cos²(x/6) = 1/2
-cos(2*x/6) = 1/2
cos(x/3) = -1/2
x/3 = ±2π/3 + 2πn, n ∈ Z
x = ±2π + 6πn , n ∈ Z