Question

помогите срочно!!по алгебре​

Answer 1

Ответ:

1)

$\sin(2x) = 2 \sin(x) \cos(x) = \\ 2 \sin(x) \sqrt{1 - \sin ^{2} (x) } = \\ 2 \times \frac{1}{ \sqrt{5} } \sqrt{1 - \frac{1}{5} } = \frac{2}{ \sqrt{5} } \sqrt{ \frac{4}{5} } = \\ \frac{4}{5}$

2)

$\frac{8 \sin(19) \cos(19) }{ \sin(38) } = \frac{4 \sin(38) }{ \sin(38) } = 4$

3)

$\frac{15 \cos(82) }{3 \cos ^{2} (41) - 3 \sin ^{2} (41) } = \frac{15 \cos(82) }{3 \cos(82) } = 5$