The Mécanique analytique presents a comprehensive account of Lagrangian mechanics. In this work, Lagrange used the Principle of Virtual Work in conjunction with the Lagrangian Multiplier to solve all problems of statics. For the treatment of dynamics, a third concept had to be added to the first two - d'Alembert's Principle - in order to develop the Lagrangian equations of motion. Hence, Lagrange was able to unify the entire science of mechanics using only three concepts and algebraic operations.
French mathematician and astronomer comte Joseph Louis Lagrange developed the calculus of variations in 1755 and made a number of other contributions to the study of mechanics.
Born Giuseppe Lodovico Lagrangia (also reported as Giuseppe Luigi Lagrangia) this man of Enlightenment era of Italy made significant contributions to the fields of analysis, number theory, classical mechanics, and celestial mechanics. He died in Paris.
In 1766, on the recommendation of Leonhard Euler and Jean Le Rond d'Alembert, Lagrange succeeded Euler as the director of mathematics at the Prussian academy of sciences in Berlin, Prussia, where he stayed for more than two decades, producing volumes of work and winning several prizes of the French Academy of Sciences. Treatise of Lagrange on analytical mechanics (Mécanique Analytique, 4. ed., 2 vols. Paris: Gauthier-Villars et fils, 1888–89), written in Berlin and first published in 1788, offered the most comprehensive treatment of classical mechanics since Newton and formed a basis for the development of mathematical physics in the nineteenth century.
In 1787, at age 51, he moved from Berlin to Paris and became a member of the French Academy. He remained in France until the end of his life. He was significantly involved in the decimalisation in Revolutionary France, became the first professor of analysis at the École Polytechnique upon its opening in 1794, founding member of the Bureau des Longitudes and Senator in 1799.