atan

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

    atan — Arco tangente

    Descripción

    atan(float $num): float

    Devuelve el arco tangente de num en radianes. atan() es la función complementaria de tan(), lo que quiere decir que a==tan(atan(a)) para cada valor de a en el rango de atan().

    Parámetros

    num

    El argumento a procesar

    Valores devueltos

    El arco tangente de num en radianes.

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    User Contributed Notes 1 note

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    9
    Anonymous
    10 years ago
    Contrary to the current description, it should hold y == tan(atan(y)) for ALL y.
    However, x == atan(tan(x)) only holds for those x which are in the range of atan, which are those x with -pi/2 < x < pi/2.

    Of course, those equalities are limited by precision. On my machine
    tan(atan(1000)) returns 1000.0000000001.
    atan(tan(0)) returns 0 (correct).
    atan(tan(M_PI)) returns -1.2246467991474E-16 instead of 0.
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