In the figure below in e1 1.64 why is i(t) negative. When switch is put to S1 position, the capacitor will start discharging. So current will flow from top plate of capacitor to resistor to bottom plate of capacitor. Where did negative sign come from in eqn. 1.64? When charging the current through capacitor is C dv/dt, flowing from top to bottom in capacitor leg. Could this have something to do with it?