# Parallel LCs circuit Lagrangian

1. Nov 12, 2011

### Goddar

1. The problem statement, all variables and given/known data
Hi, i have a quick question to see if i'm on the right track (I totally suck at electrical circuits since i never took a formal course so it might seem elementary to you.. anyway):

Three LC systems in parallel with different L and C values, nothing else. closed circuit.
First step in the problem is to formulate the Lagrangian and that's where i need a check, i'll be fine with the rest.

3. The attempt at a solution
Is it correct to write for the system:
L =T+V=$\frac{1}{2}$$\sum L_{i}\dot{q}^{2}_{i}+q^{2}_{i}/C_{i}$
With the constraint:
q$_{1}$+q$_{2}$+q$_{3}$=0
??
It seems too simple to me and i think i should be dealing with cross-terms, so a hint would be greatly appreciated.. thanks!