Find the limit of the following series As n approaches infinity, find the limit of (n/2n+1). 
I know if there was a number in place of infinity, I would plug that in for the "n". But what do I do for the infinity sign? 

Notice $$ \frac{n}{2n +1} = \frac{1}{2 + \frac{1}{n}} \to \frac{1}{2}$$
Since $\frac{1}{n} \to 0 $
Added: if  we have 
$$ \frac{n}{(2n)^3 + 1} = \frac{ \frac{1}{n^3} }{2^3 + \frac{1}{n^3}} \to 0$$
since $\frac{1}{n^3} \to 0 $
