15.2 For the oscillator described in Problem 15.1, find the characteristic equation and use it to show that, independent of the values of A and K, the poles of the circuit lie at a radial distance of ω0. Find the values of AK that results in the poles appearing (a) on the jω axis, and (b) in the right half of the s plane, at a horizontal distance from the jω axis of ω0/(2Q).