Question Number 166693 by cortano1 last updated on 25/Feb/22
$$\:\:\:\:\:\:\frac{\sqrt{\mathrm{7}}}{\mathrm{8sin}\:\frac{\pi}{\mathrm{7}}\mathrm{sin}\:\frac{\mathrm{2}\pi}{\mathrm{7}}\mathrm{sin}\:\frac{\mathrm{3}\pi}{\mathrm{7}}}\:=? \\ $$
7-8sin-pi-7-sin-2pi-7-sin-3pi-7-