1. The problem statement, all variables and given/known data The difference between the Euler and Lagrange equations and when to use each. How to set up Lagrange when the energies are non-holonomic such as friction. What is the difference between curly delta and plain derivative, eg Hamilton's equation 2. Relevant equations Euler's equation vs. Lagrange equation and Hamilton's equation 3. The attempt at a solution These are general conceptual questions. Please see the attached sheet for more detail. I just need a little more understanding rather than help on a specific problem. Links to sites giving more detailed explanations would be greatly appreciated.