Get your own PHP server Result Size: 625 x 565
x
 
<!DOCTYPE html>
<html>
<body>
<?php
echo(asin(0.64) . "<br>");
echo(asin(-0.4) . "<br>");
echo(asin(0) . "<br>");
echo(asin(-1) . "<br>");
echo(asin(1) . "<br>");
echo(asin(2));
?>
</body>
</html>
0.69449826562656
-0.41151684606749
0
-1.5707963267949
1.5707963267949
NAN