php man page for log1p

LOG1P(3)								 1								  LOG1P(3)

log1p - Returns log(1 + number), computed in a way that is accurate even when the value of number is close to zero

SYNOPSIS
       float log1p (float  $number)

DESCRIPTION
       log1p(3)  returns  log(1  +  $number) computed in a way that is accurate even when the value of $number is close to zero. log(3) might only
       return log(1) in this case due to lack of precision.

PARAMETERS
	      o $number
		- The argument to process

RETURN VALUES
	log(1 + $number)

CHANGELOG
       +--------+--------------------------------------------------+
       |Version |						   |
       |	|						   |
       |	|		    Description 		   |
       |	|						   |
       +--------+--------------------------------------------------+
       | 5.3.0	|						   |
       |	|						   |
       |	|  This function is now available on all platforms |
       |	|						   |
       +--------+--------------------------------------------------+
SEE ALSO
       expm1(3), log(3), log10(3).

PHP Documentation Group 														  LOG1P(3)