Question

Cos = 5/13 найти tg sin < 0

Answer 1

Cos = 5/13 найти tg
sin < 0

Решение.

sin=$\sqrt{1- cos^{2} } = \sqrt{1- (\frac{5}{13}) ^{2} } = \sqrt{1- \frac{25}{169} } = \sqrt{ \frac{169}{169}- \frac{25}{169} } = \sqrt{ \frac{169-25}{169} }$ 
sin=$\sqrt{ \frac{144}{169} } = \frac{12}{13}$
Т.к. sin<0  то sin=-$\frac{12}{13}$

tg=$\frac{sin}{cos} =- \frac{12}{13} * \frac{13}{5} = -\frac{12}{5}$