1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution I found ω0 = 1/√LC when IR is at its maximum. (Purely resistive) I have a feeling that the last part requires an approximation and then an expansion which gives 2 values of ω. But the thing is, (1 + x)n ≈ 1 + nx + ..... only when x << 1 In this case it's L/RC << 1 which doesn't really fit..