Calculating the reactive and active power
If the capacitor were a second resistor, you would write

$$P=\frac{U_e^2}{R_{tot}}=\frac{U_e^2}{(R_2\parallel R_3)}=\frac{U_e^2}{\frac{R_2R_3}{R_2+R_3}}$$

Same applies to this complex network:

$$P=\frac{U_e^2}{Z_{tot}}=\frac{U_e^2}{(R_2\parallel Z_{C_3})}$$

So, it's now a little more complicated to get \$\Re(P)\$ and \$\Im(P)\$, but that's just math...