Question

Determine whether the series is convergent or divergent
1. 1+1/2.sqrt(2) +1/3.sqrt(3) +1/4.sqrt(4) +...
2. Sum of n^2/(n^3+1) with n=1 -> infinite
3. Sum of (3n-4)/(n^2-2n) with n=3 -> infinite
4. Sum of 1/(n^2 +6n+13) with n=1 -> infinite