Inverse cot in C#

Question

We know that the inverse of tan is Math.Atan, what about the inverse of cot? cot(x) is defined as

cot(x)=1/tan(x)

Answer 1

See Inverse Cotangent. For some values, the inverse would be atan(1/x).

Answer 2

Another alternative for inverse of cotangent is Math.PI/2 - Math.Atan(x) which has the advantage of working properly when x is 0.