Prove that:
$\displaystyle \binom{r}{k}=\frac{r}{r-k}*\binom{r-1}{k}$
Here is as far as I've gotten:
$\displaystyle r\frac{(r-1)!}{(r-1-k)!(k)!}$
which would be equal to
$\displaystyle r\binom{r-1}{r-k}$...i think
I'm stuck for the next step.
Prove that:
$\displaystyle \binom{r}{k}=\frac{r}{r-k}*\binom{r-1}{k}$
Here is as far as I've gotten:
$\displaystyle r\frac{(r-1)!}{(r-1-k)!(k)!}$
which would be equal to
$\displaystyle r\binom{r-1}{r-k}$...i think
I'm stuck for the next step.