For a CS amplifier with gm = 5 mA/V, Cgs = 5 pF, Cgd = 1 pF, CL = 5 pF, R1 sig = 10 kΩ, and R1L = 10 kΩ, find τH and fH. What is the percentage of τH that is caused by the interaction of R_ sig with the input capacitance? To what value must R_ sig be lowered in order to double fH?