expm1

(PHP 4 >= 4.1.0, PHP 5)

expm1 --  Returns exp(number) - 1, computed in a way that is accurate even when the value of number is close to zero

Description

float expm1 ( float number)

Warning

This function is EXPERIMENTAL. The behaviour of this function, the name of this function, and anything else documented about this function may change without notice in a future release of PHP. Use this function at your own risk.

expm1() returns the equivalent to 'exp(number) - 1' computed in a way that is accurate even if the value of number is near zero, a case where 'exp (number) - 1' would be inaccurate due to subtraction of two numbers that are nearly equal.

Note: This function is not implemented on Windows platforms.

See also log1p() and exp().