모두CBT
다음 중 f(t)=e-at의 z변환은?
1z−e−at\dfrac{1}{z-e^{-at}}z−e−at1
1z+e−at\dfrac{1}{z+e^{-at}}z+e−at1
zz−e−at\dfrac{z}{z-e^{-at}}z−e−atz
zz+e−at\dfrac{z}{z+e^{-at}}z+e−atz