Solution
= Solution
\b[False.] The <sum of squares of the first n positive integers> gives
$$
\frac1{n^2}\sum_{k=1}^n k^2=\frac{n(n+1)(2n+1)}{6n^2}\geq\frac n3.
$$
This ratio is unbounded, so it cannot satisfy the constant bound required by <Big O notation>. In fact the <sum> has order $n^3$, as its leading term also shows.