Hi. There is just this one thing in mechanics which is lagrangian that I just simply can't grasp physically. I'm taking a mechanics course I simply do not understand what the lagrangian is. There is calculus of variations (at least a tiny but of it) a bit of geodesics and the least action principle which is proving also a bit elusive. Is it possible that someone may just give me a quick few sentences about the lagrangian, physically and a bit mathematically? I have tried looking up online pages but they all pretty much say the exact same thing.