# Second-order DSolve overdetermined with only 2 boundary conditions

I was going through some circuit analysis problem and came up with a second-order differential equation, which I decided to solve with Mathematica:

$$L\frac{\mathrm{d}^{2} I}{\mathrm{d}t^{2}} + R\frac{\mathrm{d}I}{\mathrm{d}t} - \frac{I}{C} = 0.$$

I used the following syntax:

DSolve[{L i''[t] + R i'[t] - i[t]/C == 0, i[0] == 0, L i'[t] == 1}, i[t], t]


Yet Mathematica returns the following error:

DSolve::overdet: There are fewer dependent variables than equations, so the system is overdetermined. >>


However, it is a second-order ODE, and so it should not be overdetermined with only two boundary conditions.

-
Did you by any chance mean L i'[0] == 1 ? –  Zet Dec 14 '13 at 23:36