Ucd(0)=18VUcd(∞)=0，τ=L/R=(1/3)/[9+(4+8)//(3+1)]=(1/3)/(9+3)=1/36Ucd(t)=18e^-36tUa(t)=(1/3)Ucd(t)x(2/3)=(2/9)(18e^-36t)=4e^-36tUb(t)=(1/3)Ucd(t)x(1/4)=(1/12)(18e^-36t)=1.5e^-36tUab(t)=Ua(t)-Ub(t)=2.5e^-36t
