Question

What is the coefficient of the last term in the binomial expansion of (x + 1)9?

0
1
9
10

Answer 1

The first and last terms have coefficients of 1. The coefficient of the n-th term is C(9, n-1) = 9!/((n-1)!(10-n)!) for n=1 to 10.

The appropriate choice is ...

... 1

Answer 2

Answer:

1

Step-by-step explanation:

Given : $(x+1)^{9}$

To Find : What is the coefficient of the last term in the binomial expansion of (x + 1)9?  

Solution :

Formula of expansion : $(x+a)^{n} =\sum_{k=0}^{n} _{n} C_k x^{k} a^{n-k}$

$(x+1)^{9} =\sum_{k=0}^{9} _{9} C_k x^{k} a^{9-k}$

So , in the last term k =9

$_{9} C_9 x^{9} a^{9-9}$

$\frac{9!}{9!*0!}x^{9}$

$1*x^{9}$

Thus the coefficient of last term is 1.

Hence option 2 is correct