## Algebra and Trigonometry 10th Edition

The identity is verified. $_nC_{n-1}=~_nC_1$
$_nC_{n-1}=\frac{n!}{[n-(n-1)]!(n-1)!}=\frac{n!}{1!~(n-1)!}=\frac{n!}{(n-1)!~1!}=~_nC_1$ It can also be verified that: $_nC_{n-1}=~_nC_1=n$