php man page for log

LOG(3)									 1								    LOG(3)

log - Natural logarithm

SYNOPSIS
       float log (float  $arg, [float  $base = M_E])

DESCRIPTION
	If the optional $base parameter is specified, log(3) returns logbase$arg, otherwise log(3) returns the natural logarithm of $arg.

PARAMETERS
	      o $arg
		- The value to calculate the logarithm for

	      o $base
		- The optional logarithmic base to use (defaults to 'e' and so to the natural logarithm).

RETURN VALUES
	The logarithm of $arg to $base, if given, or the natural logarithm.

SEE ALSO
       log10(3), exp(3), pow(3).

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