When studying a system that has the same behavior of an RLC parallel circuit, the slope of the impedance before the resonance corresponds to the value of the equivalent inductance, the slope after the resonance to the value of the equivalent capacitance and the value of the impedance at the resonance frequency to that of the resistance (phase = 0).
My question is, let's say we study an RLC circuit in real life -instead of modeling the studied system with RLC parallel circuit with constant values-, the parameters R, L and C are frequency dependent (R(f), L(f) and C(f)), then to what value of inductance (what frequency) exactly does the slope before the resonance correspond to (same for the slope after the resonance aka the capacitance)?
Thanks in advance