Question

What is the 5th term in the binomial expansion (a+b)^7

Answer 1

Answer:

On Apex

Step-by-step explanation:

35a^4 b^3

Answer 2

Answer:

5th term is 35a^4b^3

Step-by-step explanation:

We need to find the 5th term in binomial expansion (a+b)^7

The binomial theorem is:

$(x+y)^n = \sum_{n=0}^{k} {n\choose k}x^ky^{n-k}$

We are given

x=a,

y =b

n=7

and k= 4 since we have to find 5th term but k starts from zero

putting the values

$={7\choose 4}a^4b^{7-4}\\={7\choose 4}a^4b^{3}\\=\frac{7!}{4!(7-4)!}a^4b^3\\=35a^4b^3$

So, 5th term is 35a^4b^3