Question Number 166685 by cortano1 last updated on 25/Feb/22
$$\:\:\:\mathrm{sec}\:^{\mathrm{2}} \mathrm{1}°+\mathrm{sec}\:^{\mathrm{2}} \mathrm{2}°+\mathrm{sec}\:^{\mathrm{2}} \mathrm{3}°+…+\mathrm{sec}\:^{\mathrm{2}} \mathrm{89}°=? \\ $$
sec-2-1-sec-2-2-sec-2-3-sec-2-89-