Is the series 1/(n(n+1)) convergent?
n=2 to n=infinity
yes
sum of 1/n^2 = pi^2/6, and this is less than that
sum of 1/n^k converges for k>1
n=2 to n=infinity
sum of 1/n^2 = pi^2/6, and this is less than that
sum of 1/n^k converges for k>1