L'indispensable dérivée

At first glance, the derivative, at the frontier between physics and mathematics, is nothing other than the instantaneous velocity of a moving object. But how to define it more precisely? Try then, without using limits... we seem to divide zero by itself! The greatest minds, from Fermat to Cauchy, passing through Newton, took centuries to rigorously and completely generalize this concept. Yet, it is found everywhere, in everything that varies; it allows us to predict the future in any deterministic phenomenon! A current example: your tax rate and the derivative get along very well...

At the time of smart tanning, take advantage of this issue to clean up your neurons by solving mathematical puzzles, some of which are out of the ordinary! How? Don't panic! Our feature will get your brain back in the saddle by reminding you, with examples, of the main proof techniques. The essential induction and the inexhaustible pigeonhole principle are obviously on the menu. From Alcuin of York in the past to Terence Tao today, great mathematicians have always been fond of beautiful problems, while popularizers, like Martin Gardner, excelled in the art of leading you to an elegant solution.