2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/112787Some extensions of an inequality from IMO'2001 are proven by means of the Lagrange multiplier criterion.Publsihed in the Proceedings of the Thirty Second Spring Conference of the Union of Bulgarian Mathematicians (2003), 323-327; for a shorter version see Crux Math. 28 (2002), 308-312History and Overviewtext