Trigonometeric Function

\frac{2\sin\left( \frac{\pi}{18}\right)\cos\left( \frac{\pi}{18}\right)\sin\left( \frac{5\pi}{18}\right)\sin\left( \frac{7\pi}{18}\right)}{2\cos\left( \frac{\pi}{18}\right)}\\ \\ \\ \frac{2\sin\left( \frac{2\pi}{18}\right)\sin\left( \frac{5\pi}{18}\right)\cos\left( \frac{2\pi}{18}\right)}{4\cos\left( \frac{\pi}{18}\right)} \\ \\ \\ \frac{2\sin\left( \frac{4\pi}{18}\right)\sin\left( \frac{5\pi}{18}\right)}{8\cos\left( \frac{\pi}{18}\right)} \\ \\ \\ \frac{2\sin\left( \frac{4\pi}{18}\right)\cos\left( \frac{4\pi}{18}\right)}{8\cos\left( \frac{\pi}{18}\right)} \\ \\ \\ \frac{\cos\left( \frac{\pi}{18}\right)}{8\cos\left( \frac{\pi}{18}\right)} \\ \\ \\ \boxed{Ans.=\frac{1}{8}}