For the differential amplifiers below, Vinl = +Vid 2 and Vin2 =-Via 2. The cireuits are perfectly symmetrical and >0 (i.e. do not ignore ro). Find the differential voltage gains of the circuits. Indicate + and - signs for the Vout so that the gain is positive. (Hint: You can use the differential half circuit method and -GmRout method which were demonstrated during problem solving session.) VDD ERS Rs M3 Vp VDD M4. M3 M4 OVout oVout R2 o Vin2 Vint EM, M2 Vin2 Vin1 o M1 M2 Rss Rs (b) (a) Fig. 1: Differential Amplifiers