I have a homework problem that goes something like this: There's a circuit, A capacitor in parallel with a resistor, and those two are in series with another resistor. The values of the resistors are given, but the capacitor's is not. Then its given that Z(s) of the circuit equals some rational function. How do I find the value of the capacitor? I've tried finding Z(s) of the circuit in terms of C and s, and then setting it equal to the given Z(s), but to no avail.