Question

Помогите срочно пожалуйста

Answer 1

$cosa= \frac{5}{13} sina= \sqrt{1-cos ^{2}a } = \sqrt{1- (\frac{5}{13})^{2} } = \sqrt{1- \frac{25}{169} } = \sqrt{ \frac{169-25}{169} }= \sqrt{ \frac{144}{169} } = \frac{12}{13}$$sina= -\frac{3}{5} cos^{2}a= \sqrt{1-sin ^{2}a } = \sqrt{1-( -\frac{3}{5} )^{2} } = \sqrt{1- \frac{9}{25} }= \sqrt{ \frac{25-9}{25} }= \sqrt{ \frac{16}{25} } = \frac{4}{5}$