Le th\'eor\`eme des accroissements finis comme question curriculaire
  Beyond the difficulty to give true practical motives to introduce a theorem, the didactic transposition of scholarly knowledge in a school setting often leads to freezing a technical tool into a theorem given under minimal assumptions. Probably whole categories of exercises have no other justification than establishing the necessity of introducing a theorem under minimal assumptions in a curriculum. The mean value theorem represents a paradigmatic situation, showing not only the expectations of the curriculum writers, but also part of the school unconscious that manifests itself in the very notion of rigor. 
Jean-Pierre Bourgade (ADEF)
math.HO