 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, was a founding member of the Bureau des Longitudes, and became Senator in 1799.Lagrange was one of the creators of the calculus of variations, deriving the Euler–Lagrange equations for extrema of functionals.He extended the method to include possible constraints, arriving at the method of Lagrange multipliers.