numpy.arccos(x[, out]) =
Trigonometric inverse cosine, element-wise. The inverse of cos so that, if y = cos(x), then x = arccos(y). Parameters:
x : array_like x-coordinate on the unit circle. For real arguments, the domain is [-1, 1]. out : ndarray, optional Array of the same shape as a, to store results in. See doc.ufuncs (Section ?Output arguments?) for more details. Returns:
angle : ndarray The angle of the ray intersecting the unit circle at the given x-coordinate in radians [0