# 請教兩題三角函數

## 請教兩題三角函數

#### 附件

1008.zip (18.19 KB)

2016-10-8 21:18, 下載次數: 331

TOP

## 回復 1# thankyou 的帖子

\begin{align} & \sin \angle POE=\sin \left( 60{}^\circ -\angle POF \right) \\ & \frac{a}{r}=\frac{\sqrt{3}}{2}\times \frac{\sqrt{{{r}^{2}}-{{b}^{2}}}}{r}-\frac{1}{2}\times \frac{b}{r} \\ & ...... \\ \end{align}

\begin{align} & \angle PAB=60{}^\circ -\theta ,\angle PAC=120{}^\circ -\theta \\ & \\ & \frac{\overline{PB}}{\sin \left( 60{}^\circ -\theta \right)}=\frac{6}{\sin 120{}^\circ } \\ & \frac{\overline{PC}}{\sin \left( 120{}^\circ -\theta \right)}=\frac{6}{\sin 60{}^\circ } \\ & \\ & \overline{PB}=4\sqrt{3}\sin \left( 60{}^\circ -\theta \right) \\ & \overline{PC}=4\sqrt{3}\sin \left( 120{}^\circ -\theta \right) \\ & \\ & \Delta APB+\Delta APC \\ & =\frac{1}{2}\times 6\times 4\sqrt{3}\sin \left( 60{}^\circ -\theta \right)\times \sin \theta +\frac{1}{2}\times 6\times 4\sqrt{3}\sin \left( 120{}^\circ -\theta \right)\times \sin \theta \\ & =...... \\ \end{align}

[ 本帖最後由 thepiano 於 2016-10-9 09:09 PM 編輯 ]

TOP