I believe their is a pre- and post Weierstrass era of mathematics (loosely speaking). Afterwards there was epsilon-delta, before 'infinitesimals' (with certain rules, ideas and theorems, of course not holding up to todays standards).
When I read the books of Landau and Lifshitz I get the impression they are firmly grounded in the infinitesimal approach. So I would like to understand this better. So I am looking for material which would be considered a prerequesite (not looking for a modern approach). So a question would be:
- What math books would students lets say in Russia have studied before reading LL at that time?
- What math books actually follow a similiar approach?
I am not looking for modern texts (I have a firm grounding in modern mathematics), and I also do not want to translate the expressions to modern math, I just would like to know the historical math text which would have/could have been used before studying LL.