For an elementary calculus-based introduction, see Divergent series on Wikiversity
Les séries divergentes sont en général
quelque chose de bien fatal et c’est une honte qu’on ose y fonder aucune démonstration.
("Divergent series are in general something fatal, and it is a disgrace to base any proof on them." Often translated as "Divergent series are an invention of the devil …")
和