自动控制原理（双语教学）：3.8.1.5

Solution 3.8.1.5 Applying the Laplace transform, assuming zero initial conditions, yields s 3 Y (s)+5s 2 Y (s)+8sY (s)+6Y (s)=U(s)];; or (s 3 +5s 2 +8s +6)Y (s)=U(s): Rearranging yields Y (s) U(s) = 1 s 3 +5s 2 +8s +6 : 1