public static function PDF($x, $α, $β)
{
Support::checkLimits(self::LIMITS, ['x' => $x, 'α' => $α, 'β' => $β]);
$xᵃ⁻¹ = pow($x, $α - 1);
$⟮1 − x⟯ᵝ⁻¹ = pow(1 - $x, $β - 1);
$B⟮α、β⟯ = Special::beta($α, $β);
return $xᵃ⁻¹ * $⟮1 − x⟯ᵝ⁻¹ / $B⟮α、β⟯;
}