你好！
请将此示例放在 asin() 函数说明下方。
谢谢！
示例
<?php
$arg = 0.5;
$val = asin($arg);
echo "asin(" . $arg . ") = " . $val . " 弧度。<br/>";
echo "Pi 值 = " . pi() . "<br/>";
echo "asin(" . $arg . ") = " . $val/pi()*180 . " 度<br/>";
$arg = 1;
$val = asin($arg);
echo "asin(" . $arg . ") = " . $val . " 弧度。<br/>";
echo "Pi 值 = " . pi() . "<br/>";
echo "asin(" . $arg . ") = " . $val/pi()*180 . " 度<br/>";
?>