Câu hỏi 92
Chứng minh rằng
$$
\prod_{k=1}^{n-1} \sin \frac{k\pi}{n} = \frac{n}{2^{n-1}}, \quad \text{cho } n = 2, 3, \dots
$$
$$
\prod_{k=1}^{n-1} \sin \frac{k\pi}{n} = \frac{n}{2^{n-1}}, \quad \text{cho } n = 2, 3, \dots
$$
Math Olympiad Vault · MathNet 2026 — Phần 06