- Most text books give a derivation of Euler Lagrange equations from Newton’s laws using d Alembert’s principle. See for example [1, 3, 6] - If a transformation of generalized coordinates is made from \( q_k \) to another set \( Q_k \), the Lagrangian, \( L^′ \), in terms of new coordinates \( Q_k \) can be obtained by expressing the coordinates \( q_k \) in terms of new coordinates. Thus $$ L^′ (Q, \dot Q, t) = L (q(Q), \dot q (Q, \dot Q), t) \hspace{7em} (37) $$ ** 7.1 Want to learn related skills? This will be critical later for problem-solving. ** Optional now, but recommended for problem-solving later. - Simple Examples of constraints - Counting the number of independent variables to be determined - Examples of choosing generalized coordinates. ** 7.2 Want to dig deeper? or What you missed here? ** Most of this will not be required later. Here is a