Between Septembre 2016 and June 2019, I was giving the cours of Analysis for economists for L3 students of the department of Economics at the ENS. The goal was to develop the method of Lagrange multipliers in constrained optimization. Here is the text of the course, here are the slides of the introductory class, and here are the exercices:
TD 1: Dérivées partielles et premièrs calculs d'optimisation.