# Input Resistance and Mid-band Gain of a CE-CE Stage Cascade Amplifier

I am trying to calculate the Input Resistance and Mid-band Gain of a CE-CE stage.

Here's what I got so far:

I am having some doubts regarding my calculations though. Mainly with the input resistance. Can we really ignore the second transistor when calculating Rin?

What I've learned, the input resistance in emitter circuit $$\ r_e \approx r_{BE} = \beta U_T / I_C \$$, the $$\ U_T \$$ is the temperature voltage of about 26 mV at room temperature. More precisely: $$U_T = kT/e_0 = \frac{1.38\cdot10^{-23} \text{ J/K} \cdot 296 \text{ K}}{1.60\cdot 10^{-19}\text{ C}} = 25.5 \text{ mV}$$ The output doesn't influence the input resistance so much and can be neglected in that emitter circuit.