# Unity feedback gain?

In the circuit shown in Figure, $R_1 = 10 k$, $R_2 = 1k$, $C = 0.002μF$, and $L = 1μH$. If the circuit is oscillating, find the voltage gain $A$ of the forward amplifier and the frequency of oscillation

and in the solution it is provided the feedback gain $$\beta=\frac{j\omega L}{R_1-\omega^2R_2CL+j\omega(L+R_1R_2C)}$$ But I can not figure out why $\beta$ is this because when I solved for it I found $\beta =1$ by considering unity gain as Buffer Amplifier.

I want to know how $\beta$ is provided so?