4. Consider a linear time invariant system "SYS" in the following block diagram. Let y(t) be the system response when u(t) = 2e-2tu(t) is applied to the system at rest. u(t) SYS y(t) When u(t) is applied to the system at rest, -2y(t) + 4e-tu(t) is measured as the system response. u(t) SYS -2y(t) + 4e-tu(t) (a) Compute du(t) dt (b) Determine the impulse response h(t) of "SYS". (c) Compute y(t) with h(t) from (b) and u(t) = 2e-2 p(t). (d) Compute dy (t) dt and verify that y ( t) = -2y(t) + 4e-p(t)