asin()
asin() — Arc sine.
Built-in function of PHP 8.5. The manual lists it as available in PHP 4, PHP 5, PHP 7, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.
What it does
Returns the arc sine of num in radians. asin() is the inverse function of sin(), which means that $num == sin(asin($num)) for every value of num that is in the domain of asin().
Signature
asin(float $num): float
Parameters
| Parameter | Type | What it takes |
|---|---|---|
| $num | float | The argument to process |
Return value
The arc sine of num in radians
Example
The PHP manual ships no example for asin(); the signature and the parameter table above are the contract.
See also
sin(), asinh(), acos(), atan()
All PHP 8.5 built-in functions
Reference card built from the PHP manual page asin() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.