D `ALAMBER Jean le Rond (D` Alembert Jean Le Rond)

(1717-1783)
Born November 16, 1717 in Paris. In 1730 enrolled in the College of four nations, after which in 1735 received a diploma lawyer. Jurisprudence has not subsequently worked and began to study medicine. Joining and this occupation, decided to devote himself entirely to mathematics. In 1740, presented to the Academy of Sciences of the work on fluid mechanics, in 1741 was elected a member of the Academy, and in 1754 became its Permanent Secretary. Fame brought D'Alembert's treatise on the dynamics (Trait de dynamique, 1743), which was described method of reducing the dynamics of solids to static (TN. D'Alembert's principle). In 1746 in the Research on the integral calculus (Recherches sur la calcul intgral) he gave the first (not entirely rigorous) proof of the fundamental theorem of algebra on the existence of roots of algebraic equations, solution of this problem for many years worked Gauss,
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In 1747 the scientist published a paper on the theory of transverse vibrations of strings, which gave a method for solving differential equations of 2-th order partial. He has also received significant results in the theory of ordinary differential equations with constant coefficients, . introduced the concept of limit, . in the theory of series introduced a sufficient condition for the convergence, . bearing his name, thinking about the theory of probability ( 'D'Alembert's paradox'),
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D'Alembert worked with Diderot on the creation of the famous Encyclopaedia, or Explanatory Dictionary of Sciences, Arts and Crafts (1751-1772, 28 volumes). In addition to articles on mathematics and physics, wrote the introductory chapter - Essay on the origin and development of Science, which gave a classification of different areas of knowledge, to trace their origin and relationship. D'Alembert died in Paris on 29 October 1783.