*9.57 The differential amplifier in Fig. P9.57 utilizes a resistor R SS to establish a 1-mA dc bias current. Note that this amplifier uses a single 5-V supply and thus the dc common-mode voltage VCM cannot be zero. Transistors Q1 and Q2 have knW/L = 2.5 mA/V2, Vt =0.7 V, and λ = 0. (a) Find the required value of VCM. (b) Find the value of RD that results in a differential gain Ad of 8 V/V. (c) Determine the dc voltage at the drains. (d) Determine the single-ended-output common-mode gain V D1/VCM. (Hint: You need to take 1/gm into account.)(e) Use the common-mode gain found in (d) to determine the change in VCM that results in Q1 and Q2 entering the triode region.