atan2

Four-quadrant arctangent.

Syntax

C = atan2(Y, X)

Description

Returns the angle from the positive x-axis to the point (X, Y), in radians, in the range (-π, π]. Resolves the quadrant ambiguity that atan(Y/X) cannot.

Examples

atan2(1, 1)                % π/4
atan2(1, -1)               % 3π/4   (resolved correctly to upper-left)

See also

• atan2d — Four-quadrant arctangent in degrees.
• atan — Inverse tangent (radians).
• hypot — Square root of sum of squares (numerically stable).