Question

Знайти cos a, tg a, якщо sin a= -5/13,3π/2

Answer 1

$cos= \sqrt{1-(- \frac{5}{13} ) ^{2} } = \sqrt{1- \frac{25}{169} } = \sqrt{ \frac{169-25}{169} } = \frac{12}{13} \\ \\ tga= \frac{sina}{cosa} =- \frac{5}{13} : \frac{12}{13} =- \frac{5}{13} * \frac{13}{12} =- \frac{5}{12}$