D *13.51 Consider the equivalent half-circuit shown in Fig. 13.19. Assume that in the original circuit, Q1 is biased at a current I, Q7 and Q9 are biased at 2I, the dc voltage drop across R7 is 0.2 V, and the dc voltage drop across R9 is 0.3 V. Find the output resistance in terms of I, and hence find the open-circuit voltage gain (i.e., the voltage gain for RL = ∞). Now with RL connected, find the voltage gain in terms of (IRL). For RL = 1 MΩ, find I that will result in the voltage gains of 150 V/V and 300 V/V.