Question Number 180018 by cortano1 last updated on 06/Nov/22
$$\:\:\frac{\mathrm{sin}\:^{\mathrm{2}} \left(\frac{\mathrm{3}\pi}{\mathrm{7}}\right)}{\mathrm{sin}\:^{\mathrm{2}} \left(\frac{\mathrm{2}\pi}{\mathrm{7}}\right)}\:+\:\frac{\mathrm{sin}\:\left(\frac{\mathrm{3}\pi}{\mathrm{7}}\right)}{\mathrm{sin}\:\left(\frac{\mathrm{2}\pi}{\mathrm{7}}\right)}\:+\mathrm{1}−\mathrm{2sin}\:\left(\frac{\mathrm{5}\pi}{\mathrm{14}}\right)\:=? \\ $$
Commented by Frix last updated on 06/Nov/22
$$\mathrm{2} \\ $$