2000002802

SubArea: 
Combinatorics
Level: 
B
Project ID: 
2000002802
Accepted: 
0
Clonable: 
0
Easy: 
1
Simplify for \( n \in \mathbb{N}\): \[\frac{n!\cdot n!}{(n-1)!\cdot (n+1)!}\]
\( \frac{n}{n+1}\)
\( n^2 \)
\( \frac{n}{n-1}\)
\( \frac{1}{n-1}\)