- TIBCO BusinessEvents®
- Standard
- Math

# Math.acos()

## Signature

`double acos (double a)`

## Domain

ACTION, CONDITION, QUERY

## Description

Returns the arc cosine of an angle, in the range of 0.0 through pi. Special case:
If the argument is NaN or its absolute value is greater than 1, then the result is NaN.
A result must be within 1 ulp of the correctly rounded result. Results must be semi-monotonic.

## Parameters

Name | Type | Description
--- | --- | ---
`a` | `double` | The value whose arc cosine is to be returned.

## Returns

Type | Description
--- | ---
`double` | The arc cosine of the argument.

## Cautions

none