<!DOCTYPE html>
<html>
<body>
<?php
echo(tan(M_PI_4) . "<br>");
echo(tan(0.50) . "<br>");
echo(tan(-0.50) . "<br>");
echo(tan(5) . "<br>");
echo(tan(10) . "<br>");
echo(tan(-5) . "<br>");
echo(tan(-10));
?>
</body>
</html>