The circuit shown in Figure P2.51 utilizes a 10 kilohm potentiometer to realize an adjustable-gain amplifier. Derive an expression for the gain as a function of the potentiometer setting X. Assume the op amp to be ideal. What is the range of gains obtained? Show how to add a fixed resistor so that the gain range can be 1 to 11 V/V. What should the resistor value be?