源代码:
<HTML> <HEAD></HEAD> <FONT FACE="'Courier New',Verdana, Arial, Helvetica" SIZE=2> <!DOCTYPE html> <html> <body> <FONT COLOR=#ff0000><?php echo(acos(0.64) . " "); echo(acos(-0.4) . " "); echo(acos(0) . " "); echo(acos(-1) . " "); echo(acos(1) . " "); echo(acos(2)); ?></FONT> </body> </html> </HTML>
运行结果：
<HTML> <HEAD></HEAD> <FONT FACE="'Courier New',Verdana, Arial, Helvetica" SIZE=2> <!DOCTYPE html> <html> <body> <FONT COLOR=#ff0000>0.87629806116834 1.9823131728624 1.5707963267949 3.1415926535898 0 NAN</FONT> </body> </html> </HTML>