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

Essay

the switch in the circuit shown below has been closed for a long time before it is opened at t $= 0$ . Find the voltage $\mathrm { v } ( \mathrm { t } )$ across the capacitor for $\mathrm { t } \geq 0$ . Assume $\mathrm { R } _ { 1 } = 3 \mathrm { k } \Omega , \mathrm { R } _ { 2 } = 5 \mathrm { k } \Omega , \mathrm { R } _ { 3 } = 2$ $\mathrm { k } \Omega , \mathrm { I } _ { \mathrm { s } } = 4 \mathrm {~mA} , \mathrm { C } = 0.3 \mu \mathrm { F }$ .