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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.

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

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