自动控制原理（双语教学）：3.8.1.11

Solution 3.8.1.11 Applying the Laplace transform, assuming zero initial conditions, yields s 3 Y (s)+12s 2 Y (s)+36sY (s)+32Y (s)=U(s));; or (s 3 +12s 2 +36s)Y (s)=U(s): Rearranging yields Y (s) U(s) = 1 s 3 +12s 2 +36s : 1