一个三角连乘

realnumber

\[\cos{\frac{\pi}{17}}\cos{\frac{2\pi}{17}}\cos{\frac{3\pi}{17}}\cos{\frac{4\pi}{17}}\cos{\frac{5\pi}{17}}\cos{\frac{6\pi}{17}}\cos{\frac{7\pi}{17}}\cos{8\frac{\pi}{17}}\]

realnumber

乘除\[2^8\sin{\frac{\pi}{17}}\sin{\frac{3\pi}{17}}\sin{\frac{5\pi}{17}}\]
\[2^4\sin{\frac{\pi}{17}}\cos{\frac{\pi}{17}}\cos{\frac{2\pi}{17}}\cos{\frac{4\pi}{17}}\cos{\frac{8\pi}{17}}=\frac{\sin{\frac{\pi}{17}}}{2^4}\]
\[2^4\sin{\frac{3\pi}{17}}\cos{\frac{3\pi}{17}}\cos{\frac{6\pi}{17}}=\sin{\frac{5\pi}{17}}\]
\[2^4\sin{\frac{5\pi}{17}}\cos{\frac{5\pi}{17}}\cos{\frac{7\pi}{17}}=\sin{\frac{3\pi}{17}}\]

realnumber

刀歌0.57721

色k

回复 3# realnumber

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