# 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 arg )

**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(`arg`

) - 1' computed in a way that is
accurate even if the value of `arg`

is near zero,
a case where 'exp (`arg`

) - 1' would be
inaccurate due to subtraction of two numbers that are nearly equal.

**Note: **This function is not
implemented on Windows platforms.

## Parameters

`arg`

The argument to process

## Return Values

'e' to the power of `arg`

minus one