^{-1}(x) I have to do tan-

^{1}(1/x). Then add either pi, or 180 depending on wheather we are using radians or degrees.

And I don't understand this. If x is cot, then when we do 1/x, shouldn't we get tan? And after than isn't it enough to just do tan

^{-1}(1/x) to get the answer? What is the point of adding that pi or 180 degrees?