tryphp_func_math_atanh.php:
<!DOCTYPE html> <html> <body> <?php echo(atanh(M_PI_4) . "<br>"); echo(atanh(0.50) . "<br>"); echo(atanh(-0.50) . "<br>"); echo(atanh(1) . "<br>"); echo(atanh(-1)); ?> </body> </html>
1.0593061708232
0.54930614433405
-0.54930614433405
INF
-INF