回復 2# huanghs 的帖子
第7題
作\(\overline{CE}\)垂直直線\(AB\)於\(E\)
令\(\overline{BD}=x,\overline{AB}=\overline{CD}=1\)
則\(\overline{AE}=\frac{1}{x},\overline{CE}=\frac{\sqrt{3}}{x}\)
\(\begin{align}
& {{\left( 1+\frac{1}{x} \right)}^{2}}+{{\left( \frac{\sqrt{3}}{x} \right)}^{2}}={{\left( x+1 \right)}^{2}} \\
& \sec B=x=\sqrt[3]{2} \\
\end{align}\)
