Question #d48ce

1 Answer
Oct 23, 2017

The coefficient of x^5 is 4032

Explanation:

The expansion (1+2x)^9 is of the form (1+X)^n
The general term in the expansion (1+X)^n is
T_(r+1)=C_r(X)^n
Here X=2x and n=5
on substituting we get
(9!)/(4!.5!)(2x)^5 rArr126*32 x^5
The coefficient of x^5 is 126*32=4032
:. coefficient of (x)^5=4032