Description
The acos() function calculates the arc cosine value of the number provided as its only parameter, essentially reversing the operation of cos(). The return value is in radians—you should use the rad2deg() to convert radians to degrees.
$acos1 = acos(0.4346); $acos2 = acos(cos(80));
Syntax:
acos(float $num): float
Parameters
| Parameter | Description |
|---|---|
| num | The argument to process |
Return Values
The arc cosine of num in radians.
Example
Calculate the arccosine of a value
$cos = 0.5; echo "The arccosine of $cos is ", acos($cos);