French mathematician who was a disciple of Euler and Lagrange. He published a classic work on geometry, Élements de géométrie. He also made significant contributions in differential equations, calculus, function theory, number theory Essai sur la théorie des nombres (1797-98), and applied math. He expanded his three-volume treatise Exercises du calcul intégral (1811-19) into another three volume work, Traité des fonctions elliptiques et des intégrales eulériennes (1825-32). Legendre reduced elliptic integrals to three standard forms, but their straightforward inversion by Abel and Jacobi rendered his work unnecessary. He invented the Legendre polynomials in 1784 while studying the attraction of spheroids. His work was important for geodesy. In number theory, he proved the unsolvability of Fermat's last theorem for n=5.

Additional biographies: MacTutor (St. Andrews), Dublin Trinity College, Bonn