Câu hỏi 50
Với mọi số nguyên $n \ge 1$, chứng minh rằng
$$
\sum_{k=1}^{n} \frac{2^k}{\sqrt{k+0.5}} \le 2^{n+1}\sqrt{n+1} - \frac{4n^{3/2}}{3}.
$$
$$
\sum_{k=1}^{n} \frac{2^k}{\sqrt{k+0.5}} \le 2^{n+1}\sqrt{n+1} - \frac{4n^{3/2}}{3}.
$$
Math Olympiad Vault · MathNet 2016-part-05 — 184 bài (EN–VI)