如圖,經(jīng)過原點(diǎn)O的直線與圓M:(x+1)
2+y
2=4相交于A,B兩點(diǎn),過點(diǎn)C(1,0)且與AB垂直的直線與圓M的另一個(gè)交點(diǎn)為D.
(1)當(dāng)點(diǎn)B坐標(biāo)為(-1,-2)時(shí),求直線CD的方程;
(2)記點(diǎn)A關(guān)于x軸對(duì)稱點(diǎn)為F(異于點(diǎn)A,B),求證:直線BF恒過x軸上一定點(diǎn),并求出該定點(diǎn)坐標(biāo);
(3)求四邊形ABCD的面積S的取值范圍.