Question

Вычислите sin a,tg a, если соs a =-3/4 и π/2

Answer 1

Решение во вложении...

Answer 2

$frac{pi} {2}< alpha< pi \\Sinalpha>0\\Sin alpha= sqrt{1-Cos^{2}alpha} = sqrt{1-(-frac{3}{4})^{2}}= sqrt{1-frac{9}{16}}= sqrt{frac{7}{16}}= frac{sqrt{7}} {4}\\tgalpha =frac{Sinalpha} {Cosalpha} = frac{sqrt{7}} {4}: (-frac{3}{4})=- frac{sqrt{7} } {4}* frac{4}{3}=- frac{sqrt{7}} {3}$