In an example about oscillator
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?
