Challenging question on binomial series that students always ask during H2 math tuition.

[@bentpc]

I would suggest showing a more general term of (1 - x)^-n for integer values of n as (n + r - 1) C (r - 1).
Of course I understand that in A levels Maths, the power of n in (1 - x)^ -n would be restricted to at most 2 especially in the extension of series expansion after partial fractions. Cheers

[@jksolame]

watching it hours before the paper lol.