Answer
Show that $(_k^n) \leq 2^n$ for all positive integers n and all integers k with k 0≤k≤n.
Work Step by Step
The sum of all the positive numbers $(_k^n)$, as k runs from 0 to n, is equal to $2^n$. In other words, $\sum_{k=0}^{n}(_k^n) = 2^n$. So each one of them is cannot be bigger than this sum.
