idk what ur on about butlol x^2n isnt a constant?
What you're saying is like "
....
this is what i meant (soz i just explain things badly lol)eyy hoes you gotta remember the leading coefficient wasnt 1 rip
e.g. you can expand the second term in the part (ii) expression and you get -(2nC2) x^(2n-2+2) or some shit
so the leading coefficient isn't 1, but rather some disgustingly huge expression