Solve 2cosx - √3 = 0 for x ∈ [0, 2π].

add radical 3 to both sides then divide by 2 so that cos x = √3/2. You can then use the inverse cosine function on your calculator or your knowledge of special right triangles or the unit circle to figure out that one of the angles is 30 degrees. this is the angle in the 1st quadrant. However there is another angle in the 4th quadrant that has the same value. Use the 30 degree angle as the reference angle in the fourth quadrant to find that 330 degrees will also give you the same answer. In radians these values are π/6 and 11π/6