# In Physics Given a system with [[generalized coordinates|generalized coordinates]] $q^i$, [[Newton's second law|Newton's second law]] can be written as the Euler-Lagrange Equation: $ \frac{d}{dt} \frac{\partial L}{\partial \dot{q}^i} - \frac{\partial L}{\partial q^i} = 0 $ where $L$ is the [[Lagrangian]].