If you do a google search for how to derive the facts that and , most of the derivations you’ll find rely on knowing something like the double angle formula and go through a direct, non-trivial evaluation of . It’s actually possible to compute these derivatives this without really remembering any specific facts about trigonometry […]

You can often get the gist of a mathematical subject via an informal explanation involving infinitesimals. But I often find that questions arise from that informal explanation that I’d like resolved, but I don’t want to jump all the way to the full definitions. Without a rigorous basis for reasoning about infinitesimals, it can be […]