1. The problem statement, all variables and given/known data R=50Ω L=5H C=1/125F vs=200.[1+u(t)] V Find i(t) 2. Relevant equations 3. The attempt at a solution Write the KCL equation -vs+Ri+L.i'+1/C.∫idt=0 Do the derivation to get rid of the integral, replace all possibly values, we got: i''+10i'+25i=1/5.vs' (*) solve A(s)=s2+10s+25=0, we got the natural response in(t)=A1+A2.e-5t Replace the inductor with a short circuit, the capacitor with open circuit, so I have ip=0 and the initial condition i(0+)=i(0-)=0. (**) So the solution should be i(t)=in+ip I thought I was wrong at (**) and maybe at (*) cause the vs' would be zero and the solution would be zero as well.