exp

    (PHP 4, PHP 5, PHP 7, PHP 8)

    exp — Calculates the exponent of e

    Опис

    exp(float $num): float

    Returns e raised to the power of num.

    Зауваження:

    'e' is the base of the natural system of logarithms, or approximately 2.718282.

    Параметри

    num

    The argument to process

    Значення, що повертаються

    'e' raised to the power of num

    Приклади

    Приклад #1 exp() example

    <?php
    echo exp(12) . "\n";
    echo     exp(5.7);
    ?>

    Поданий вище приклад виведе:

    1.6275E+005
298.87

    Прогляньте також

    • log() - Natural logarithm
    • pow() - Exponential expression

    Found A Problem?

    Learn How To Improve This Page • Submit a Pull Request • Report a Bug
    ＋add a note

    User Contributed Notes 1 note

    up
    3
    zooly at globmi dot com
    14 years ago
    PHP does not have the following math function in any extensions:frexp() - Extract Mantissa and Exponent of the Floating-Point ValueI've digged many C source codes, and found the simplest implementation as follows:<?phpfunction frexp ( $float ) {  $exponent = ( floor(log($float, 2)) + 1 );  $mantissa = ( $float * pow(2, -$exponent) );  return(    array($mantissa, $exponent)  );}print_r(frexp(0.0345));print_r(frexp(21.539));?>Array(    [0] => 0.552    [1] => -4)Array(    [0] => 0.67309375    [1] => 5)I have compared the results using a lot of floats against C's frexp function - they are the same.Note that C and PHP uses different float precisions, for example "4619.3" gives:C: 0.56387939453125, 13PHP: 0.563879394531, 13/Assuming default configurations./
    ＋add a note
    To Top