What is the expression for betashy- if ainbsp 105nbspand ai

Question

Consider the op-amp circuit in Figure. The op-amp has a finite gain, so that i_o = A_iε, and a zero output impedance.

(a) Write the closed-loop transfer function in the form

(b) What is the expression for β­?

(c) If A_i = 10⁵ and A_{i f} = 25, what is the required βi and R_F /R₃?

(d) If Ai decreases by 15 percent, what is the percent change in A_{i f}?