Before revision: In other words, the mirror has a finite output (or Norton) resistance given by the ro of the output transistor, namely: {I_C} \ } where VA is the Early voltage; and VCE, the collector-to-emitter voltage of output transistor.
After revision: or r_o = \frac{V_AIn other words, the mirror has a finite output (or Norton) resistance given by the ro of the output transistor, namely: {I_C} \ } where VA is the Early voltage; and VCE, the collector-to-emitter voltage of output transistor.