Question Number 129147 by Adel last updated on 13/Jan/21
$$\mathrm{cot}^{\mathrm{2}} \boldsymbol{\pi}/\mathrm{7}+\mathrm{cot}^{\mathrm{2}} \mathrm{2}\boldsymbol{\pi}/\mathrm{7}+\mathrm{cot}^{\mathrm{2}} \mathrm{3}\boldsymbol{\pi}/\mathrm{7}=? \\ $$
Commented by benjo_mathlover last updated on 13/Jan/21
$$\:\mathrm{ans}\::\:\mathrm{5} \\ $$
Commented by Adel last updated on 13/Jan/21
$$\mathrm{pleas}\:\:\mathrm{solve}\:\:\mathrm{sir} \\ $$