4.
\(I\)為等腰三角形\(ABC\)的內心\(\overline{AB}=\overline{AC}\),\(\overline{ID}\bot \overline{BC}\)、\(\overline{IE}\bot \overline{AC}\)、\(\overline{IF}\bot \overline{AB}\)。若\(\Delta AFE\)的面積等於\(\Delta FBD\)與\(\Delta EDC\)的面積和,求\(\displaystyle \frac{\overline{AF}}{\overline{BF}}=\)?
想請教第四題,謝謝!