Question Number 122044 by rs4089 last updated on 13/Nov/20
Commented by JDamian last updated on 13/Nov/20
$$\mathrm{What}\:\mathrm{is}\:\:{C}_{{r}} ? \\ $$
Commented by rs4089 last updated on 13/Nov/20
$$\frac{{n}!}{{r}!\:{n}−{r}!} \\ $$
Commented by JDamian last updated on 13/Nov/20
but that has really two parameters (n and r) and your expression only has one