# Function Reference

ACos

Calculates the arcCosine of a number.

ACos ( expression )

Parameters

expression | Any value between -1 and 1 inclusive.

Return Value

Returns the trigonometric arccosine of expression. Result is in radians.

Remarks

ACos(x) is mathematically defined only for -1 < x < 1, so ACos tends to return -1.#IND for other values of x.

Related

Sin, Cos, Tan, ASin, ATan

Example

$x = ACos(0.5)
$pi = 3.14159265358979
$radToDeg = 180 / $pi
$y = ACos(-1) * $radToDeg ;arcCosine of -1 returns 180°