Determine if the following series is convergent or divergent .

$\displaystyle 3-\frac{1}{2n},3-\frac{2}{3n},3-\frac{3}{4n},...$

I know it is a convergent series and it converges to 3 but i am unsure how to show it .

I tried ..

$\displaystyle \lim _{n \rightarrow \infty }{u_n}=3$

I am also not sure how to find $\displaystyle u_n$ ..

Thanks ..