自动控制原理（双语教学）：3.8.1.1

Solution 3.8.1.1 Applying the Laplace transform, assuming zero initial conditions, yields s 3 Y (s)+4s 2 Y (s)+3sY (s)=U(s);; or (s 3 +4s 2 +3s)Y (s)=U(s): Rearranging yields Y (s) U(s) = 1 s 3 +4s 2 +3s : 1