The sensitivity of the (b), (d), (f) real and (c), (e), (g) imaginary parts of the eigenfrequencies to (b), (c) gyration resistance, (d), (e) positive capacitance C₁ (f), (g) positive inductance L₁ perturbation. Solid lines: solution of eigenvalue problem of equatoin (18); green-dashed lines: Puiseux series approximation truncated to its second term. Here, the EPD frequency is unstable, i.e., EPD frequency is purely imaginary. Voltage v₁ (t) for the unstable EPD condition in the time-domain, which increases exponentially over time.