Person: Carré, Louis
Louis Carré was a French mathematician who published the first French book on the integral calculus.
Mathematical Profile (Excerpt):
 In particular, Carré now had a home, living with Malebranche who became his friend as well as his employer.
 It was in this remarkable atmosphere of learning and scholarship that Carré, who was in many ways a country lad lacking in the ways of sophisticated Paris, was taught mathematics and metaphysics by Malebranche.
 He spent seven years as Malebranche's secretary which gave Carré the equivalent of a university education.
 The language of Carré being rather unpolished and ungrammatical, one of his fair pupils offered to give him lessons in French, in return for his philosophical instructions.
 Carré cheerfully accepted the offer, and often acknowledged himself greatly indebted to the instructions which he then received.
 At this stage, Carré seems to have been interested mainly in philosophy and, other than teaching mathematics, did not take much interest in current mathematical research.
 This stimulated Carré's interest in mathematics and, from this time on, he began working hard on writing a calculus text.
 In Une methode pour Ia mesure des surfaces Ⓣ(A method for measuring the area of surfaces), the first French textbook on the integral calculus, Carré made a mistake in calculating the integral for the moment of inertia of a cone suspended from its vertex, a mistake that led to an incorrect expression for the centre of oscillation of the cone.
 Although leading mathematicians such as Johann Bernoulli were aware of weaknesses in Carré's book, his error was never publicly identified and indeed was carried over into the textbooks Treatise on Fluxions, or an Introduction to Mathematical Philosophy (1704) by Charles Hayes (16781760), and The Method of Fluxions, both Direct and Inverse (1730) by Edmund Stone.
Born 26 July 1663, Colfontaine, near Nangis, Brie, France. Died 11 April 1711, Paris, France.
View full biography at MacTutor
Thank you to the contributors under CC BYSA 4.0!
 Github:

 nonGithub:
 @JJO'Connor
 @EFRobertson
References
Adapted from other CC BYSA 4.0 Sources:
 O’Connor, John J; Robertson, Edmund F: MacTutor History of Mathematics Archive