Consider a system with transfer-function G(s) = 2/(s + 1). A unit step function u(t) is applied to the system, which results in an output y(t). If \(\lim\limits_{t \to \infty} \) e(t) = y(t) − u(t), then \(\lim\limits_{t \to \infty} \)e(t)limt→∞e(t)limt→∞