His theorem in abstract algebra says a subgroup's order must divide the group's order, and he proved that each positive integer can be expressed as a sum of four squares.
This man improved upon Brouncker's continued fractions method to obtain a generalized solution of Pell's equations. His theorem in abstract algebra says a subgroup's order must divide the group's order, and he proved that each positive integer can be expressed as a sum of four squares. His work on the 3-body problem led to his namesake points, where the gravitational attraction of two bodies is balanced. For 10 points, name this French mathematician who lends his name to method of optimization which uses a name namesake multiplier and is useful when geometric constraints are present.
This man improved upon Brouncker's continued fractions method to obtain a generalized solution of Pell's equations.
Joseph Louis {Lagrange}