Short answer: It varies. Sometimes in math the history provides helpful context and motivation, and when people leave it out it makes things confusing. I'm no

Short answer: It varies. Sometimes in math the history provides helpful context and motivation, and when people leave it out it makes things confusing. I'm not going to elaborate on this because I assume most people here already agree with this! But sometimes the modern way is so much cleaner and better, so that even if you do want to learn the history, everything will probably be easier to understand if you learn the modern way first and know in advance what truth it is that they were working their way towards. Sometimes the historical way is just awful. (When I took representation theory in college, the professor thought it would be funny to at one point show us the original definition of an irreducible character. Nobody should ever have to learn representation theory in such a way!)