Example 4 S E R Assume that the switch S is open for t<0 and closed at t=0,and is open again at t=t1>0.Obtain a mathematical model for the circuit and obtain an equation for the current i(t). 日6Example 4 Assume that the switch S is open for t<0 and closed at t=0, and is open again at t=t1>0. Obtain a mathematical model for the circuit and obtain an equation for the current i(t)