ArcTan

ArcTan[z] gives the arc tangent (inverse tangent) of z. ArcTan[x, y] gives the arc tangent of y/x, taking into account which quadrant the point is in.

Examples

Compute arc tangent values:

ArcTan[1]
(* Pi/4 *)

(* Two-argument form for quadrant-aware computation *)
ArcTan[1, 1]
(* Pi/4 *)

ArcTan[-1, 1]
(* 3 Pi/4 *)

Please visit the official Wolfram Language Reference for more details.