3.5.1.2.15 Atan2

Contents

Description

The atan2 function is a variation of . For a given coordinates \((x, y)\), \(atan2(y, x)\) is the angle between the positive X axis and the point \((x, y)\). The angle is positive for counter-clockwise angles (where \(y > 0\)), and negative for clockwise angles (where \(y < 0\)). The result angle range is \((-\pi , \pi ]\), and for both x and y are zeroes, \(atan2(0, 0) = 0\).

Returned values are in radians, degrees or gradians, depending upon (which can also be set in ).

Syntax

double Atan2(double y, double x)

Parameters

y

The y value of coordinate \((x, y)\).

x

The x value of coordinate \((x, y)\).

Return

Return the angle between the positive X axis and the point given by the coordinates \((x, y)\).

Example

atan2(4, 3) = ;  // 0.92729521800161
atan2(0, -1) = ;  // 3.1415926535898
atan2(0, 0) = ;  // 0
atan2(-1, -1) = ;  // -2.3561944901923

See Also

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