Question Number 19117 by sandy_suhendra last updated on 05/Aug/17
$$\underset{\mathrm{n}=\mathrm{1}} {\overset{\mathrm{7}} {\sum}}\:\frac{\mathrm{n}}{\left(\mathrm{n}^{\mathrm{2}} +\mathrm{1}\right)}\:=\:? \\ $$$$\mathrm{please}\:\mathrm{help} \\ $$