Inverse cosine in radians
Y = acos(X)
Y = acos(X) returns the inverse cosine (arccosine) for each element of X. For real elements of X in the domain [–1, 1], acos(X) is real and in the range [0, π]. For real elements of X outside the domain [–1, 1], acos(X) is complex.
The acos function operates element-wise on arrays. The function's domains and ranges include complex values. All angles are in radians.