Question

Решите пожалуйста А1,А2,А3. Дам 95 баллов

Answer 1

$cos^{2}\alpha = 1 - sin^{2} \alpha\\cos\alpha =\sqrt{ 1 - \frac{1}{4}\\ \cos\alpha= \frac{\sqrt{3}}{2}$

$tg^{2} \alpha +1=\frac{1}{cos^{2}\alpha } \\tg\alpha = \sqrt{\frac{1}{cos^{2}\alpha }-1} \\tg\alpha =\sqrt{\frac{25}{16}-\frac{16}{16} } \\tg\alpha = \sqrt{\frac{9}{16}} \\tg\alpha = \frac{3}{4} \\tg\alpha = 0.75$

$tg\alpha =\frac{BC}{AC} \\\\\tg\alpha =\frac{2}{7}$