정답
$\sum_{k=1}^n k^2 = \frac{n(n + 1)(2n + 1)}{6}$.
해설
Similarly, $\sum_{k=1}^n k = \frac{n(n + 1)}{2}$ and $\sum_{k=1}^n k^3 = \left[\frac{n(n + 1)}{2}\right]^2$. These identities frequently appear in sequence problems.
홈 / 라이브러리 / CSAT (Suneung) essentials: original practice / AI 플래시카드
In CSAT Mathematics, how is the summation formula $\sum_{k=1}^n k^2$ calculated?
덱 'CSAT (Suneung) essentials: original practice'의 플래시카드.