自动控制原理（双语教学）：3.8.1.3

Solution 3.8.1.3 Applying the Laplace transform, assuming zero initial conditions, yields s 3 Y (s)+5s 2 Y (s)+12sY (s)+8Y (s)=U(s);; or (s 3 +5s 2 +12s +8)Y (s)=U(s): Rearranging yields Y (s) U(s) = 1 s 3 +5s 2 +12s +8 : 1