QUESTION 3 Given a system Sy has an impulse response hy and system Sy has an impulse response h2, then the combined system response when Stand S2 are connected in cascade would be o hy+h2 o hy.hz o hy h2 o hilha QUESTION 4 if the roots of a system's characteristic equation are purely imaginary, its response will be unstable O imaginary sinusoidal exponential