*해설

<문제 해설>
δ(t) => F(s) = 1, F(z) = 1
u(t) => F(s) = 1/S , F(z) = Z/(Z-1)
t => F(s) = 1/S^2, F(z) = Tz/(Z-1)^2
e^-at => F(s) = 1/S+a, F(z) = Z/(Z-e^-at)