Question

1) Найдите cosa, tga, ctga если sina=-0.8
2) Найдите cosa, tga, ctga если sina=$frac{sqrt{2} }{3}$

Answer 1

$cosa = sqrt{1 - {sin}^{2} a} \ cosa = sqrt{1 - {( - 0.8)}^{2} } = sqrt{1 - 0.64} = sqrt{0.36} = 0.6 \ tga = frac{sina}{cosa} \ tga = frac{ - 0.8}{0.6} = - frac{4}{3} \ ctga = frac{cosa}{sina} \ ctga = frac{0.6}{ - 0.8} = frac{3}{4}$

cosa =sqrt(1 - 2/9) =sqrt(7)/3
tga = (sqrt(2)/3)/(sqrt(7)/3) =(sqrt(2))/(sqrt(7))
ctga=(sqrt(7)/3)/(sqrt(2)/3) =(sqrt(7))/(sqrt(2))

Answer 2

1) sina=0,8, Cosa, sina