RC combination that will define a low-cutoff frequency. + Exercise Prove the following formula V₁ C R V f AV /tan¯'(fi/f) V₁ √√1 + (fi/f)² magnitude of A, phase by which V, leads V Z=R+-j/(2*pi*f*C) Av = Vo/Vi=R / (R+jXc) = 1/ (1+jXc/R) Au C fj Where: f= 2TRC