LOG1P(): log(1 + number)

<?Php
echo LOG1P(6);// Output is 1.9459101490553
echo "<br>";
echo LOG1P(-0.3);// Output is -0.35667494393873
echo "<br>";
echo LOG1P(0.4);// Output is 0.33647223662121
echo "<br>";
echo LOG1P(1.2);// Output is 0.78845736036427
?>

LOG1P(X);