108學測數學考科-G

---

<選填題>如圖（此為示意圖），\(A, B, C, D\)為平面上的四個點。已知\(\overset{\rightharpoonup}{BC}= \overset{\rightharpoonup}{AB}+\overset{\rightharpoonup}{AD}\)，\(\overset{\rightharpoonup}{AC}, \overset{\rightharpoonup}{BD}\)兩向量等長且互相垂直，則\(\tan \angle BAD = \) __________。