英文试题 1.（20 分）The discrete-time system is shown in the following figure， () s(0.1 1) k Gs s   , T=0.1. (1) Obtain the closed-loop impulsive transfer function. (2) Determine the stable range of k. (3) If k=1, Obtain e(∞) for r(t)=1(t)+t. (Note: 368