y=arccos(x) Graph
	Y (Degrees) Y (Radian) X 180 ̊ π -1 150 ̊ 5π/6 -0.866025 135 ̊ 3π/4 -0.707107 120 ̊ 2π/3 -0.5 90 ̊ π/2 0 60 ̊ π/3 0.5 45 ̊ π/4 0.707107 30 ̊ π/6 0.866025 0 ̊ 0 1