Step-by-step explanation:
1) if m(∠A)∈[0;90°), then
[tex]cos(A)=\sqrt{1-sin^2A} =\frac{3}{5};[/tex]
[tex]sin2A=2sinAcosA=2*\frac{3}{5} *\frac{4}{5}=\frac{24}{25};[/tex]
[tex]cos2A=cos^2A-sin^2A=\frac{9}{25}-\frac{16}{25}=-\frac{7}{25};[/tex]
[tex]tan2A=\frac{sin2A}{cos2A}=-\frac{\frac{24}{25}}{\frac{7}{25}}=-\frac{24}{7}.[/tex]
2) if m∠A∈[90°;180°), then
cos(A)=-0.6;
sin2A=-0.96;
cos2A=-0.28;
tan2A=-24/7.
