## CoconutJJ one year ago Explain how the binomial theorem works with Combinations: nCk-1*X^(n-(k-1))*Y^k-1

1. anonymous

you want to expand the combination only?

2. anonymous

if you want a formula for combination then here you go $nCr = \frac{ n!}{ (n-r)!r! }$

3. anonymous

^^ exactly right.

4. anonymous

you will find the combinatorics will match the lines of pascals triangle.