Sin(Пи-A)=0.6 A принадлежит (90:180)найтиtg2A

Решите задачу:

$sin( \pi - \alpha )=0.6 \\ sin( \pi - \alpha )=sin \alpha \\ sina=0.6 \\ \\ cosa=- \sqrt{1-sin ^{2} \alpha } =- \sqrt{1-0.6 ^{2} } =- \sqrt{1-0.36} = \\ =- \sqrt{0.64} =-0.8 \\ \\ \\ tg \alpha = \frac{sin \alpha }{cos \alpha } = \frac{0.6}{-0.8} =- \frac{0.6}{0.8} =- \frac{6}{8} =- \frac{3}{4} \\$

$\\ tg2 \alpha = \frac{2tg \alpha }{1-tg ^{2} \alpha } = \frac{2*(- \frac{3}{4}) }{1-( -\frac{3}{4} ) ^{2} } = \frac{- \frac{3}{2} }{1- \frac{9}{16} } =- \frac{ \frac{3}{2} }{ \frac{16}{16}- \frac{9}{16} } = \\ =- \frac{ \frac{3}{2} }{ \frac{7}{16} } =- \frac{3}{2} / \frac{7}{16} =- \frac{3*16}{2*7} =- \frac{3*8}{7} =- \frac{24}{7} =- 3\frac{3}{7}$