Answer
The identity is verified.
$_nP_{n-1}=~_nP_n$
Work Step by Step
$_nP_{n-1}=\frac{n!}{[(n-(n-1)]!}=\frac{n!}{1!}$
But, $1!=1=0!$
$_nP_{n-1}=\frac{n!}{1!}=\frac{n!}{0!}=\frac{n!}{(n-n)!}=~_nP_n$
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