2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/60675Some divergent trigonometric integrals have appeared in standard tables for many years, listed as converging. We give a simple proof that these integrals diverge and trace their history. The original error was made when a (startlingly) famous mathematician incorrectly differentiated under the integral sign with some convergent integrals that depend on a paramater.to appear in a slightly different version in Amer. Math. MonthlyClassical Analysis and ODEs26A42text