# Documentation/Calc Functions/ATAN

Other languages:
dansk • ‎English

ATAN

Mathematical

## Summary:

Returns the inverse trigonometric tangent (the arctangent) of a number. This function calculates the principal value.

ATAN(Number)

## Returns:

This function returns the inverse trigonometric tangent of Number, that is the angle (in radians) whose tangent is Number. The angle returned is between -PI/2 and PI/2, i.e. [-π/2,+π/2].

## Arguments:

Number is the real number, or a reference to a cell containing that number whose inverse trigonometric tangent value is to be calculated.

• To return the angle in degrees, use the DEGREES function.
• Alternatively multiply by 180/PI() to convert the result from radians to degrees.

The GIF below illustrates the function ATAN.

ATAN function

## Examples:

Formula Description Returns
=ATAN(1) Inverse trigonometric tangent of 1 0.785398163397448 (PI/4 radians or π/4)
=ATAN(0.5) Inverse trigonometric tangent of 0.5 0.463647609000806 (radians)
=DEGREES(ATAN(1)) Inverse trigonometric tangent of 1. Further, converting angle in radians to degrees. 45° (degrees)
=ATAN(-1)*180/PI() Inverse trigonometric tangent of -1. Further, converting angle in radians to degrees by multiplying by 180/PI(). -45° (degrees)

ACOS

ASIN

TAN

## ODF standard:

Section 6.16.9 ,part 2

ATAN