Atan2 Function

Returns the arctangent of the point whose coordinates are x and y. The arctangent is the angle from the x-axis to a line drawn through the origin (0,0) and a point with coordinates x, y.

Syntax

result = Atan2( y, x )


Parameters

y

Double

y coordinate of the point.

x

Double

x coordinate of the point.


Return Value

Result

Double

Arctangent of the point (y, x) in radians.



Notes

The result is expressed in radians. To convert it to degrees, multiply it by 180/PI.

The converse operations are done with Cos and Sin. That is, if you have an angle and want to find an x, y pair along the line described by 0,0 and x,y, you can do so with:

x = Cos(angle)*radius
y= Sin(angle)*radius

Examples

This example uses the Atan2 function to return the arctangent of a point directly above the origin.

Dim d as Double
Const PI=3.14159265358979323846264338327950
d=Atan2(1,0) //returns 1.57
d=Atan2(1,0)*180/PI //returns 90

See Also

Atan, Tan functions.