A two-branch parallel circuit has a resistance of 20 in one branch and the series combination

A two-branch parallel circuit has a resistance of 20 Ω in one branch and the series combination of R = 10 Ω and L = 0.1 H in the other. First, apply an excitation, I_i(s), and obtain the natural frequency from the denominator of the network function. Try different locations for applying the current source. Second, insert a voltage source, V_i(s), and obtain the natural frequency.