public static function CDF(int $k, float $p) : float { Support::checkLimits(self::LIMITS, ['k' => $k, 'p' => $p]); $⟮1 − p⟯ᵏ⁺¹ = pow(1 - $p, $k + 1); return 1 - $⟮1 − p⟯ᵏ⁺¹; }