# Documentation/How Tos/Calc: ATAN function

From Apache OpenOffice Wiki

## ATAN

Returns the inverse tangent (the arctangent) of a number.

### Syntax:

**ATAN(number)**

- returns the inverse trigonometric tangent of
, in other words the angle (in radians) whose tangent is**number**. The angle returned is between**number**and**-PI/2**.**PI/2**

- To return the angle in degrees, use the
function.**DEGREES**

### Example:

**ATAN(1)**

- returns
(**0.785398163397448**radians).**PI/4**

**DEGREES(ATAN(1))**

- returns
. The tangent of**45**degrees is**45**.**1**