===== Syntax ===== float asin(float $val) //(PHP 4, PHP 5)// ^ $val | Value to compute the arc sine for. | ^ RETURNS | Computes the trigonometry function ''arc sine'' for the degree in radians (**$val**). | ===== What it Does ===== This function computes the arc sine for the argument **$val** which is the degree in radians. ===== Example ===== // compute the arc sine for 1.4 radians echo 'asin(1.4) = ' . asin(1.4);