Дано: Sina+Cosa=1/2; 3П/4 меньше ПНайти: tg2a Ctg2a

[latex]sina+cosa=\frac{1}{2}\\ sin^2a+cos^2a=1\\\\ 1+2sina*cosa=\frac{1}{4}\\\\ sin2a=-\frac{3}{4}\\ cos2a=\frac{\sqrt{7}}{4}\\ tg2a=\frac{-\frac{3}{4}}{\frac{\sqrt{7}}{4}}}=-\frac{3}{\sqrt{7}}\\ ctg2a=-\frac{\sqrt{7}}{3}[/latex]