# ACOS

Returns the arc cosine of expression x.

ACOS(x)

## Description

The absolute value of x must be less than or equal to 1. The returned value ranges from $\left[0,\pi \right]$ . Thus, $0\le ACOS\left(x\right)\le \pi$

## Arguments

x
Any valid function expression.

## Example

<Reference_Variable
id                  = "1"
label               = "ACOS Example"
type                = "EXPRESSION"
expr                = "ACOS(AY(569,193))"
/>