The purpose of this paper is to study the symmetry of first order Lagrangians and the corresponding conserved quantity. The relation between the Lagrangians and the Birkhoff’s functions and the Birkhoff symmetry of Birkhoffian systems are used to obtain the symmetry of first order Lagrangians and the corresponding conserved quantity. Two examples are given to illustrate the application of the result.
The purpose of this paper is to study the symmetry of first order Lagrangians and the cor- responding conserved quantity. The relation between the Lagrangians and the Birkhoff' s functions and the Birkhoff symmetry of Birkhoffian systems are used to obtain the symmetry of first order La- grangians and the corresponding conserved quantity. Two examples are given to illustrate the appli- cation of the result.