tryphp_func_math_log1p.php:
<!DOCTYPE html> <html> <body> <?php echo(log1p(2.7183) . "<br>"); echo(log1p(2) . "<br>"); echo(log1p(1) . "<br>"); echo(log1p(0)); ?> </body> </html>
1.3132665745863
1.0986122886681
0.69314718055995
0