12. For the network of Fig. 9.74:
a. Determine the mathematical expression for the angle by which Va leads V,.
b. Determine the phase angle at ( = 100 Hz, 1 kHz, 2 kHz, 5 kHz, and 10 kHz, and plot the resulting curve for the frequency range of 100 Hz to 10 kHz.
c. Determine the break frequency.
d. Sketch the frequency response of 8 for the frequency spectrum of part (b) and compare results.