Documentation/Calc Functions/ATAN
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Function name:
ATAN
Category:
Mathematical
Summary:
Calculates the inverse trigonometric tangent (arctangent or arctan) of a real number. The value returned is the principal value and lies in the range (-π/2, π/2) radians.
Syntax:
ATAN(Number)
Returns:
Returns a real number in the range (-π/2, π/2) that is the inverse trigonometric tangent of Number in radians.
Arguments:
Number is a real number, or a reference to a cell containing that number, whose inverse trigonometric tangent is to be calculated.
- If Number is non-numeric, then ATAN reports a #VALUE! error.
 
Additional details:
- To return the angle in degrees, use the DEGREES function.
 - Alternatively multiply by 180/PI() to convert the result from radians to degrees.
 
The figure below illustrates the function ATAN.

Examples:
| Formula | Description | Returns | 
|---|---|---|
| ATAN(−1) | Inverse trigonometric tangent of -1. | −0.785398163397448 (-π/4) | 
| =ATAN(D1) where cell D1 contains the number 0.5. | Inverse trigonometric tangent of 0.5. | 0.463647609000806 | 
| =DEGREES(ATAN(0.5)) | Inverse trigonometric tangent of 0.5, converted to degrees. | 26.565051177078 | 
| =ATAN(−0.5)*180/PI() | Inverse trigonometric tangent of -0.5, converted to degrees. | −26.565051177078 | 
| =DEGREES(ATAN(TAN(RADIANS(60))) | An angle of 60° is converted to radians, its tangent is taken, then the inverse tangent of that value is calculated, and finally the result is converted back to degrees. | 60 | 
Related LibreOffice functions:
ODF standard:
Related (or similar) Excel functions:
ATAN