sin$\frac\pi 7\cdot $ sin$\frac{2\pi} 7\cdot $ sin $\frac{3\pi} 7\cdot$ sin $\frac{4\pi} 7 \cdot $ sin$\frac{5\pi} 7 \cdot $sin $\frac{6\pi} 7 \cdot $ sin $\frac{7\pi} 7 $ = $\frac 7 {64}$
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Need help urgently!!
sin$\frac{7\pi} 7 = 0$, so how come this be proved!!