Упрости выражения

1. \(\cfrac{P\_{n+3}}{(n+1)P\_n}=\) [ ].

2. \(\cfrac{P\_{n+4}}{(n+2) P\_n}=\) [ ].

3. \(\cfrac{(n+2)P\_{n+1}}{P\_{n+4}}=\) [ ].

4. \(\cfrac{P\_{n+5}}{(n+3)P\_{n+2}}=\) [ ].