Resposta :
[tex]cosx=\sqrt{1-sen^2x} \\
\\
cosx=\sqrt{1-(\frac{3}{5})^2} \\
\\
cosx=\sqrt{1-\frac{9}{25}} \\
\\
cosx=\sqrt{\frac{16}{25}}=\frac{4}{5}[/tex]
[tex]tgx=\frac{senx}{cosx}=\frac{\frac{3}{5}}{\frac{4}{5}}=\frac{3}{4} \\ [/tex]
Sendo do 4o. quadrante tg x = -3/4
[tex]tgx=\frac{senx}{cosx}=\frac{\frac{3}{5}}{\frac{4}{5}}=\frac{3}{4} \\ [/tex]
Sendo do 4o. quadrante tg x = -3/4