a French mathematician, physicist and philosopher who was the first to find and solve the wave equation. D'Alembert also helped to resolve the controversy in mathematical physics over the conservation of kinetic energy by improving Newton's definition of force in his Traité de dynamique that he published in 1743. He also was a pioneer in the study of partial differential equations and their applications in physics. He went on to edit the famous 28 volume Encyclopédie, for which d'Alembert wrote most of the mathematical and scientific articles.