Question

A din n+2 luate cite n =360 rezolvati ecuatia (COOMBINATORICA)

Answer 1

[tex]A_{n+2}^{n}=360\\ \frac{(n+2)!}{(n+2-n)!}=360=\ \textgreater \ \frac{(n+2)!}{2!}=360=\ \textgreater \ (n+2)!=720\\ (n+2)!=6!=\ \textgreater \ n=4[/tex]