MathPHP\Probability\Distribution\Continuous\Weibull::PDF PHP Метод

    public static function PDF($x, $k, $λ)
    {
        Support::checkLimits(self::LIMITS, ['k' => $k, 'λ' => $λ]);
        if ($x < 0) {
            return 0;
        }
        $k／λ = $k / $λ;
        $⟮x／λ⟯ᵏ⁻¹ = pow($x / $λ, $k - 1);
        $ℯ⁻⁽x／λ⁾ᵏ = exp(-pow($x / $λ, $k));
        return $k／λ * $⟮x／λ⟯ᵏ⁻¹ * $ℯ⁻⁽x／λ⁾ᵏ;
    }