Documentation/Calc Functions/ATAN2
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Function name:
ATAN2
Category:
Mathematical
Summary:
Calculates the inverse trigonometric tangent (arctangent or arctan) for the specified x and y coordinates. That is, the angle (in radians) between the x-axis and a line from the origin to the specified (x, y) point. The value returned is the principal value and lies in the range (-π, π] radians.
Syntax:
ATAN2(Number X; Number Y)
Returns:
Returns a real number in the range (-π, π] that is the inverse trigonometric cosine in radians for the specified x and y coordinates.
If the function returns a positive angle it represents a counterclockwise angle from the x-axis, while a negative result represents a clockwise angle.
Arguments:
Number X is a real number, or a reference to a cell containing that number, that is the value of the x coordinate.
Number Y is a real number, or a reference to a cell containing that number, that is the value of the y coordinate.
- If either Number X or Number Y is non-numeric, then ATAN2 returns a #VALUE! error.
- If Number X and Number Y are both equal to 0, then ATAN2 returns the value 0.
Additional details:
The following illustration shows the geometry used by ATAN2 (φ is the angle calculated).
- To return the angle in degrees, use the DEGREES function.
- Alternatively multiply by 180/PI() to convert the result from radians to degrees.
- Beware that computer programming languages often use the opposite order of arguments for their atan2() functions.
Examples:
| Formula | Description | Returns |
|---|---|---|
| =ATAN2(−5; 9) | Here the function calculates the angle (in radians) between the x-axis and a line from the origin to the point (-5, 9). | 2.07789483118723 |
| =DEGREES(ATAN2(12.3; 12.3)) | Here the function calculates the angle (in degrees) between the x-axis and a line from the origin to the point (12.3, 12.3). | 45 |
| =ATAN2(D1; D2) where cells D1 and D2 both contain the value 0. | Here the function returns 0. | 0 |
| =ATAN2(−5; −3)*180/PI() | Here the function calculates the angle (in degrees) between the x-axis and a line from the origin to the point (-5, -3). | −149.036243467926 |
| DEGREES(ATAN2(−8; 5)) | Here the function calculates the angle (in degrees) between the x-axis and a line from the origin to the point (-8, 5). | 147.994616791916 |
Related LibreOffice functions:
ODF standard:
Related (or similar) Excel functions:
ATAN2