Question

Найти sin x,если cos x =-5/13 pi

Answer 1

$Sinx=- \sqrt{1-Cos ^{2} x} =- \sqrt{1-( -\frac{5}{13}) ^{2} } = - \sqrt{1- \frac{25}{169} }=- \sqrt{ \frac{144}{169} }=$$- \frac{12}{13}$