expm1

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

expm1 — Returnsexp($num) - 1, computed in a way that is accurate even when the value of number is close to zero

Description

expm1() returns the equivalent toexp($num) - 1 computed in a way that is accurate even if the value ofnum is near zero, a case whereexp($num) - 1 would be inaccurate due to subtraction of two numbers that are nearly equal.

Parameters

num

The argument to process

Return Values

e to the power ofnum, minus one.

See Also

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