ATAN2
Returns the arctangent of the specified x and y coordinates (the angle of a line that crosses the origin (0,0) and a point with x_num, y_num coordinates). The angle is in radians, in the range –pi to pi, excluding the value –pi.
Syntax
ATAN2(x_num;y_num)
X_num is the point’s x coordinate.
Y_num is the point’s y coordinate.
Comment
A positive result signifies a counterclockwise angle with the x axis, while a negative result signifies a clockwise angle.
ATAN2(a;b) equals ATAN(b/a), but in the ATAN2 function, a can be equal to 0.
If the x_num and y_num values are 0, the ATAN2 function returns the error value #DIV /0!.
In order to express the arctangent in degrees, you have to multiply the result by 180/pi(), or use the DEGREES function.