9. 計算題(15分) Figure P9 shows a feedback current amplifier formed by cascading an inverting voltage amplifier μ with a MOSFET Q. For the case of μ= 100 V/V, Rs == ∞, R1 = 10 kΩ, and R2 = 90 kΩ; For Q:gm = 5 mA/V and ro = 20 kΩ.