The level I was shooting for with my brief explanation was that someone who understood limits at a calc 1 level should be able to get it with a little thinking. I do wonder, though: did you know those things before you read my comment?
Cool. Sounds like you're in grad school right now, yeah? I know differential geometry is not exactly the same as differential topology, but I remember taking differential topology in grad school. I was always amused that we never actually evaluated any integrals that didn't come out to a very simple number (generally 0).
If I were writing this as a web page, though, I would definitely include a few graphs to explain the calculus concepts. The amount of calculus you need here is pretty intuitive once you draw a couple of pictures.
