4u math

Hello Board of Studies Users, I just want to know a simple question: If you do math extension 2 (4 units), are the internal assessments for math advanced used for your HSC Marks, or is it that Maths Advanced does not count to the HSC at all? I am asking this because I have seen some sources...

How do i prove this, also am i able to assume that coeff friction ≥0?

Next term, after finishing advanced math, I will be starting math E1 and E2 simultaneously, I know some of the E1 content due to common content with physics (vectors) but I was wondering if this workload will be too much. My school decided to start E1 and E2 in term 4 so I have not done any...