expm1

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

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

    Description

    expm1(float $num): float

    expm1() returns the equivalent to exp($num) - 1 computed in a way that is accurate even if the value of num is near zero, a case where exp($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 of num, 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

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