各位大侠帮助求拉氏反变换（s^3）/(（s^2+3*s+2）*s).

Question

各位大侠帮助求拉氏反变换 （s^3）/(（s^2+3*s+2）*s).

Answer 1

F(s)=（s^3）/(（s^2+3*s+2）*s)
=1-（3s+2）/(s^2+3*s+2)
=1-(3s+2)/(s+1)(s+2)
=1+1/(s+1)-4/(s+2)
故f(t)=δ(t)+[e^(-t)-4*e^(-2t)]ε(t)