Question 19
Prove that
$$
tan \left(\frac{3 \pi}{11}\right)+4 \sin \left(\frac{2 \pi}{11}\right)=\sqrt{11}
$$
$$
tan \left(\frac{3 \pi}{11}\right)+4 \sin \left(\frac{2 \pi}{11}\right)=\sqrt{11}
$$
MathNet 2026 — Part 09 Question 19
Math Olympiad Vault · MathNet 2026 — Part 09