∑from 1 to ∞(n^2+4)/(n^2+ n)
your general term (n^2+4)/(n^2+ n) will approach 1 as n --->∞
e.g. term (100) = 10,004/10,100 = .99048....
term(5000) = .9998..
so you are adding appr (.... +1+1+1+1+1+....) for an infinite number of times
What do you think?