The ATAN2 function returns the arctangent, or inverse tangent, of the specified x- and y-coordinates. The arctangent is the angle from the x-axis to a line containing the origin (0, 0) and a point with coordinates (x_num, y_num). The angle is given in radians between -pi and pi, excluding -pi.

ATAN2 takes 2 required arguments and no optional arguments:

Syntax: ATAN2(x_num, y_num)

##### Using the ATAN2 function:
The arguments for the ATAN2 function are:
Argument Required? Description
x_num Required The x-coordinate of the point.
y_num Required The y-coordinate of the point.
##### A few more things:
 • A positive result represents a counterclockwise angle from the x-axis; a negative result represents a clockwise angle. • ATAN2(a,b) equals ATAN(b/a), except that a can equal 0 in ATAN2 • If both x_num and y_num are 0, ATAN2 returns the #DIV/0! error value. • To express the arctangent in degrees, multiply the result by 180/PI( ) or use the DEGREES function

### Summary

The ATAN2 function returns the arctangent, or inverse tangent, of the specified x- and y-coordinates.