An important concept in Lagrangian mechanics is that of a generalised coordinate, <math>q_k</math>. The position coordinate <math>q_k</math> and corresponding velocity coordinate <math>\dot q_k</math> are taken to be independent of each other so that: | An important concept in Lagrangian mechanics is that of a generalised coordinate, <math>q_k</math>. The position coordinate <math>q_k</math> and corresponding velocity coordinate <math>\dot q_k</math> are taken to be independent of each other so that: |