PHP function acos()
Availability in PHP 4.0
Arcus cosinus (arcus cosinus).
The function returns the arcus cosine of the parameter $arg in radians. The acos() function is the inverse of the cos() function, which means that $a === cos(acos($a)) (note the rounding!) for every value in the definition domain of the acos() function.
Parameters
| Parameter | Data type | Default value | Note |
|---|---|---|---|
$arg |
float |
not | Argument to process. |
Return values
float
Returns the arc cosine of the argument in radians.