2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56744Let $lu = -u^{\prime \prime} + q(x)u$, where $q(x)$ is a real-valued $L^2_{loc}(0, \infty)$ function. H. Weyl has proved in 1910 that for any $z$, $Imz \neq 0$, the equation $(l - z)w=0$, $x>0$, has a solution $w \in L^2(0, \infty)$. We prove this classical result using a new argument.Mathematical Physics34B25, 34B20text