Question

Найдите cosa, tga, ctga, если sina 15/17?​

Answer 1

Ответ:

$cosa=\sqrt{1-sin^2a}=\sqrt{1-(\frac{15}{17} )^2} =\sqrt{1-\frac{225}{289} } =\sqrt{\frac{289-225}{289} } =\sqrt{\frac{64}{289} } =\frac{8}{17}$

$tga=\frac{sina}{cosa} =\frac{\frac{15}{17} }{\frac{8}{17} } =\frac{15}{8}$

$ctga=\frac{cosa}{sina} =\frac{\frac{8}{17} }{\frac{15}{17} } =\frac{8}{15}$

Объяснение: