The Switch 1 in the Circuit Shown Below Has Been $t = 0$

Essay

the switch 1 in the circuit shown below has been closed for a long time before it is opened at $t = 0$ , and the switch 2 has been opened for a long time before it is closed at $t = 0$ . Find the current $i ( t )$ through the inductor for $t \geq 0$ . Assume $R _ { 1 } = 100 \Omega , R _ { 2 } = 200 \Omega , R _ { 3 } = 400 \Omega , L = 90$ $\mathrm { mH } , \mathrm { C } = 0.02 \mu \mathrm { F } , \mathrm { I } _ { \mathrm { s } } = 3 \mathrm {~mA} , \mathrm {~V} _ { \mathrm { s } } = 6 \mathrm {~V}$ .