21．（本小题满分12分）
[2017皖南八校
]如图，点
<Object: word/embeddings/oleObject1.bin>
，<Object: word/embeddings/oleObject2.bin>
分别为椭圆
<Object: word/embeddings/oleObject3.bin>
的左右顶点，
<Object: word/embeddings/oleObject4.bin>
为椭圆<Object: word/embeddings/oleObject5.bin>
上非顶点的三点，直线
<Object: word/embeddings/oleObject6.bin>
的斜率分别为
<Object: word/embeddings/oleObject7.bin>
，且<Object: word/embeddings/oleObject8.bin>
，<Object: word/embeddings/oleObject9.bin>
，<Object: word/embeddings/oleObject10.bin>
．（1）求椭圆
<Object: wor ...