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.
Syntax
ATAN2(x_num,y_num)
X_num is the x-coordinate of the point.
Y_num is the y-coordinate of the point.
Remarks
- 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.
Examples
| Formul a | Description (Result) |
|---|---|
| =ATAN2(1, 1) | Arctangent of the point 1,1 in radians, pi/4 (0.785398) |
| =ATAN2(-1, -1) | Arctangent of the point -1,-1 in radians, -3*pi/4 (-2.35619) |
| =ATAN2(-1, -1)*180/PI() | Arctangent of the point 1,1 in degrees (-135) |
| =DEGREES(ATAN2(-1, -1)) | Arctangent of the point 1,1 in degrees (-135) |