Question

Тригонометрия. Хелп ми

Answer 1

$Cos alpha = sqrt{1-Sin ^{2} alpha } = sqrt{1 - ( -frac{1}{ sqrt{17} } ) ^{2} } = sqrt{1- frac{1}{17} } = sqrt{ frac{16}{17} } = frac{4}{ sqrt{17} }$
$tg alpha = frac{Sin alpha }{Cos alpha } = frac{ -frac{1}{ sqrt{17} } }{ frac{4}{ sqrt{17} } } =- frac{1}{4}= - 0,25$