2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/53851It is shown that linear time-dependent invariants for arbitrary multi\-dimensional quadratic systems can be obtained from the Lagrangian and Hamiltonian formulation procedures by considering a variation of coordinates and momenta that follows the classical trajectory and defines a noetherian symmetry transformation.Plain TeX, 9 pages, preprint of Instituto de Ciencias Nucleares, UNAM Departamento de F\ii sica and Matemáticas Aplicadas, México D. F. , México No. 03 (1994)High Energy Physics - Theorytext