a) [tex3]\text{sen}\alpha=2\cos\beta.[/tex3]
b) Se [tex3]\overline{BC}=3 \text{cm}[/tex3] e [tex3]\text{tg}\frac{\beta}{2}=\frac{1}{2},[/tex3] então [tex3]\overline{CD}=2\text{cm}.[/tex3]
c) [tex3]\text{tg}\alpha+\text{tg}\beta=\frac{x^2}{yz}.[/tex3]
d) [tex3]\cos\frac{\beta}{2}=\frac{x}{y}.[/tex3]
e) [tex3]\text{sen}\frac{\beta}{2}=\frac{x}{\overline{CD}}.[/tex3]