# ATn function (LotusScript® Language)

Returns the arctangent, in radians, of a number.

## Syntax

**ATn** **(** *numExpr* **)**

## Elements

*numExpr*

Any numeric expression.

## Return value

ATn returns the angle, in radians, whose tangent
is equal to the value of *numExpr*.

The range of the return value is -pi/2 (-90 degrees) to pi/2 (90 degrees), exclusive.

The data type of the return value is Double.