2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/142206We find a geometrical method of analysing the singularities of a plane nodal curve. The main results will be used in a forthcoming paper on geometric Plucker formulas for such curves. Plane nodal curves, that is plane curves having at most nodes as singularities, form an important class of curves, as any projective algebraic curve is birational to a plane nodal curve.Algebraic GeometryLogictext