你好！
请将以下示例放在asin()函数描述的下方。
谢谢！
示例
<?php
$arg = 0.5;
$val = asin($arg);
echo "asin(" . $arg . ") = " . $val . " radians.<br/>";
echo "Pi value = " . pi() . "<br/>";
echo "asin(" . $arg . ") = " . $val/pi()*180 . " degrees<br/>";
$arg = 1;
$val = asin($arg);
echo "asin(" . $arg . ") = " . $val . " radians.<br/>";
echo "Pi value = " . pi() . "<br/>";
echo "asin(" . $arg . ") = " . $val/pi()*180 . " degrees<br/>";
?>