An inverting amplifier is accidentally connected with positive feedback as illustrated in Fig….

An inverting amplifier is accidentally connected with
positive feedback as illustrated in Fig. P2.29. Assuming the op amp has a
finite gain A, find an expression for the
closed-loop gain, v0/v1. Show that if A = 1 + (R 2/R1),
the closed-loop gain becomes infinite, indicating instability.
Real op-amp gain varies with input frequency so that insta-bility is
practically inevitable when positive feedback is used.