$4.$ Calculate the closed$-$loop gain and output resistance of the amplifier in Figure $3$ below at relatively low frequencies where C$1$ and C$2$ load the amplifier negligibly.

Hints:

Break the feedback loop at the top plate of C$1$ to find the open loop gain.

Calculate the loop gain, $\backslash ($ V$\_\{\backslash$text $\{$out $\}\}/$ V$\_\{$x$\}\backslash )$ using Figure $4.$

Figure $4$