Help to use mathematical induction to prove that the square of 1 / 2 + 1 / 3 is always less than 1 when it is added to the square of 1 / n Notice that it's 1 / 2!

Help to use mathematical induction to prove that the square of 1 / 2 + 1 / 3 is always less than 1 when it is added to the square of 1 / n Notice that it's 1 / 2!

1 / N ^ 2 < 1 / [n (n-1)] = 1 / (n-1) - 1 / n it's easy to know this
1/4+1/9+1/16+…… 1/N^2 = 1/2^2 + 1/3^2 + 1/4^2 + ...+ 1/N^2