Problem - 4345
Show that $$\frac{1}{(1-ax)^n}=\sum_{k=0}^{\infty}a^k\binom{n-k}{n-1}x^k$$
Replacing $x$ with $ax$ in the conclusion of # 4284.
Show that $$\frac{1}{(1-ax)^n}=\sum_{k=0}^{\infty}a^k\binom{n-k}{n-1}x^k$$
Replacing $x$ with $ax$ in the conclusion of # 4284.