A differential amplifier connected in the circuit in the given figure has the parameters listed below with RI = 6.0 kΩ and RL = 450 Ω: Input resistance Rid = 1.2 MΩ Output resistance RO = 20 Ω A = 40 dB vi = Vlsinωt What is the amplitude VI of the sinusoidal input signal needed to develop a 20−V peak-to-peak signal at vO ? (Round the final answer to one decimal place.) The amplitude VI is = mV