3. ABCD 為圓內接四邊形, \(\overline{AB} = 1, \overline{BC} = 7, \overline{CD} = 5, \overline{DA} = 5, \overrightarrow{AC} = \alpha \overrightarrow{AB} + \beta \overrightarrow{AD}\),求數對 \((\alpha, \beta)\)。
3. ABCD 為圓內接四邊形, \(\overline{AB} = 1, \overline{BC} = 7, \overline{CD} = 5, \overline{DA} = 5, \overrightarrow{AC} = \alpha \overrightarrow{AB} + \beta \overrightarrow{AD}\),求數對 \((\alpha, \beta)\)。