Brachystochrona
Paul Embrechts is Professor of Mathematics at the ETH Zurich specializing in Actuarial Mathematics and Quantitative Risk Management. Previous academic positions include the Universities of Leuven, Limburg and London (Imperial College). Dr. Embrechts has held visiting professorships at several universities, including the Scuola Normale in Pisa (Cattedra Galileiana), the London School of Economics (Centennial Professor of Finance), the University of Vienna, Paris 1 (Panthéon-Sorbonne), theNationalUniversity...
Dans un mémoire publié en 1774, Lagrange utilise des méthodes reposant sur l’analogie des puissances positives et des différences, et des puissances négatives et des sommes, qui lui permettent, notamment, d’obtenir diverses formules d’intégration. D’autres auteurs s’engagent alors dans cette voie. Les problèmes de calcul intégral jouent un rôle important dans le développement de diverses formes de calcul symbolique et celui-ci fait la preuve de son efficacité dans ce domaine : il permet de généraliser...
The word caustic was introduced by Tschirnhausen in 1686, in the Latin expression caustica curva. We show that the study of the optical caustics goes back well before, at least to the hellenistic period. We present a small Greek text, whose author is perhaps Geminus (1st cent. B.C.), describing an optical phenomenon called achilles. We show that the term achilles, which has appeared only once, to our knowledge, in the literature, means caustics by reflection. We complete the description of the achilles...