送交者: HunHunSheng 于 2009-03-13, 10:01:06:

回答: why? only used the triangle formed by A, C1 and C2 and an arbituary (x,y) 由 chouqilozi 于 2009-03-13, 09:55:57:

• 装糊涂？当然可以证明横竖坐标轴上那四点满足椭圆轨迹的要求 (无内容) - fuzzify (0 bytes) 2009-03-13, 10:11:45 (306154)
• 坐标是可以随意选取的 at (x0,y0). (无内容) - chouqilozi (0 bytes) 2009-03-13, 10:04:42 (306149)

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