I have already self-studied all the contents of IB maths AA HL and now I’m doing basic college maths like calculus for example.
As for past essays no I haven’t, choosing maths for the extended essay topic is rare in my school. The teacher is supportive and she told me I needed to come up with a topic by this October, and I hope to make my essay not only good for EE in IB but also for academic research, which is vital for college application.