2e的-3/2t次方 u(t )
f(0+)=lim(s->∞)sF(s) =lim(s-->∞) s(2s+3)/(s+1)2=2 f(∞)=lim(s->0)sF(s) =lim(s-->0) s(2s+3)/(s+1)2=0
