Inequality a1 + A2 / 2 ^ 2 + A3 / 3 ^ 2 +... + an / N ^ 2 ≥ 1 + 1 / 2 +... + 1 / n

Inequality a1 + A2 / 2 ^ 2 + A3 / 3 ^ 2 +... + an / N ^ 2 ≥ 1 + 1 / 2 +... + 1 / n

It seems that your question lacks conditions. For example, A1 = - 1, A2 = - 2, A3 = - 3 This formula is not correct
Cauchy's construction can give you: a (A1 under 1 / radical) ^ 2 + (A2 under 1 / radical) ^ 2 + (A3 under 1 / radical) ^ 2 + +(1 / under the root sign an) ^ 2 is OK