C2 Binomial Expanison help

Hi, i have got an awnser to the below question part a, but im not sure if its right and i need help with part b.

In the binomial expansion, in ascending powers of x, of (1+ax)n, where a and n are constants, the coeffiecnt of x is 15. The coefficient of x2 and x3 are equal.

a) Find the value of a nad the value of n

b)find the coefficient of x3

any help is much appriciated

Reply 1

james.h

11

beccajonesy

Hi, i have got an awnser to the below question part a, but im not sure if its right and i need help with part b.

In the binomial expansion, in ascending powers of x, of (1+ax)n, where a and n are constants, the coeffiecnt of x is 15. The coefficient of x2 and x3 are equal.

a) Find the value of a nad the value of n

b)find the coefficient of x3

any help is much appriciated