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已知ＡＤ与ＢＣ交于Ｅ ,ＡＣ∥ＦＥ∥ＢＤ .(图一 )求证 :1ＡＣ+1ＢＤ =1ＦＥ.图一这是一个常见的几何题 ,它有较为丰富的潜能 .若对它进行开发 ,以用于初三复习或第二课堂教学 .则在培养学生的探究能力方面将收到事半功倍的教学效果 .下面本文在原条件不变及尽量不加新线段 (?
It is known that AD and BC are intersected by E, and AC∥FE∥BD (Fig. 1) is verified: 1AC+1BD = 1FE. Figure 1 This is a common geometric problem. It has more abundant potential. If it is developed, For the third grade review or the second classroom instruction, you will receive more effective teaching results in cultivating the student’s inquiry ability. The following article will remain unchanged in the original conditions and try not to add new lines (?