Cos β= 4\5 3π\2 меньше β меньше 2π найти:sinβ,tgβ,ctgβ

[latex] cos^2 \beta+sin^2 \beta=1[/latex] [latex]\frac{3\pi}{2}<\beta<2\pi[/latex] => [latex]sin \beta<0[/latex] [latex]sin \beta=-\sqrt{1-cos^2 \beta}=\\\\-\sqrt{1-(\frac{4}{5})^2}=\frac{3}{5}[/latex] [latex]tg \beta=\frac{sin \beta}{cos \beta}=\frac{3}{5}:\frac{4}{5}=\frac{3}{4}[/latex] [latex]ctg \beta=\frac{cos \beta}{sin \beta}=\frac{4}{5}:\frac{3}{5}=\frac{4}{3}[/latex]