Resumen

TORRES DEL CASTILLO, G.F.; ANDRADE MIRON, C.  y  BRAVO ROJAS, R.I.. Variational symmetries of Lagrangians. Rev. mex. fís. E [online]. 2013, vol.59, n.2, pp.140-147. ISSN 1870-3542.

We present an elementary derivation of the equation for the infinitesimal generators of variational symmetries of a Lagrangian for a system with a finite number of degrees of freedom. We also give a simple proof of the existence of an infinite number of Lagrangians for a given second-order ordinary differential equation.

Palabras llave : Lagrangians; symmetries; constants of motion; ordinary differential equations.