Recall that you must choose a set of independent coordinates PRIOR to using Lagrange’s equations. One way to verify that your choice of generalized coordinates are independent is to: hold all but one ...

I SHOULD fancy from the review by “G. H. B.” in NATURE of July 19 (p. 265) that the papers of Prof. Levi Civita relate largely to the mixed transformation of Lagrange's equations, the complete theory ...