2.10.112 Number Series

Condition: explore the ranks for the convergence: 1) \ (\ sum_ {n = 1}^{\ infty} \ frac {3 n} {5 n+1} \), 2) \ (\ sum_ {n = 1}^{\ infty} \ frac {(n+1)^{2}} {n^{4} +2 n^{2} +1} \) 3) \ (\ sum_ {n = 1}^\ infty} \ tan \ frac {1} {n}} \)