Question

What do you mean by binomial coefficient ​

Answer 1

Binomial coefficient:

In mathematics, the binomial coefficients are the positive integers that occur as coefficients in the binomial theorem. Commonly, a binomial coefficient is indexed by a pair of integers n ≥ k ≥ 0 and is written
`n C_(r)`.

It is the coefficient of the
`x^(k)` term in the polynomial expansion of the binomial power
`(1+x)^(k)`, and it is given by the formula

`n C_(r)=((n) !)/((n-r) !(r) !)`