Another approach to infinitesimal calculus which allows a presentation in a relatively clear elementary way is smooth infinitesimal analysis and related synthet

Another approach to infinitesimal calculus which allows a presentation in a relatively clear elementary way is smooth infinitesimal analysis and related synthetic differential geometry: http://home.sandiego.edu/~shulman/papers/sdg-pizza-seminar.pdf http://home.sandiego.edu/~shulman/papers/sdg-pizza-seminar.p...