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