# ATAN

Returns the arctangent, or inverse tangent, of a number. The arctangent is the angle whose tangent is number. The returned angle is given in radians in the range -pi/2 to pi/2.

## Syntax

ATAN(number)


### Parameters

Term Definition
number The tangent of the angle you want.

## Return value

Returns the inverse hyperbolic tangent of a number.

## Remarks

To express the arctangent in degrees, multiply the result by 180/PI( ) or use the DEGREES function.

## Example

Formula Description Result
= ATAN(1) Arctangent of 1 in radians, pi/4 0.785398163
= ATAN(1)*180/PI() Arctangent of 1 in degrees 45