tryphp_func_math_asin.php:
<!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