expm1
(PHP 4 >= 4.0.7, PHP 5)
expm1 — Returns exp(number) - 1, computed in a way that is accurate even when the value of number is close to zero
說明
float expm1
( float $arg
)
Warning
本函式是實驗性的。這個函式的行為、名稱、和關於此函式的任何其他文件在未來PHP的發行中可能會在不通知的情況下改變。 使用此函式需自行承擔風險。
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: 本函式未在 Windows 平台下實作。
參數
- arg
-
The argument to process
Return值
'e' to the power of arg minus one