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[几何] 一个高三模拟考 向量题

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realnumber Posted 2016-4-14 13:48 |Read mode
QQ图片20160414134447.png
\[\vv{AP}=\vv{AO}+\vv{OP},O为正五边形中心\]

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游客 Posted 2016-4-14 15:05
回复 1# realnumber


    恩,就是求外接圆半径X5。

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色k Posted 2016-4-14 15:10
嗯,简单题

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敬畏数学 Posted 2016-4-15 16:43
O为正多边形A1A2A3......An的中心
=> OA1+OA2+..+OAn=0
这个结论应该是成立的,物理上很容易证明此结论,另外用复数也可以。除这两方法外有其他方法吗?请教。。。。。

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 Author| realnumber Posted 2016-4-15 18:23
回复 4# 敬畏数学


  偶数边,那么都有相反向量.
奇数边,由图形的对称,所有和的方向是任意的,可见为零向量.

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kuing Posted 2016-4-15 18:47

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走走看看 Posted 2017-10-22 07:14
回复 3# 色k


    请解释一下,点P在哪里的时候取得最大值,答案是哪个。

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色k Posted 2017-10-22 09:50
回复 7# 走走看看

同学,基础题要自己动手完成哦,况且前面几楼已经有了提示呐。

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kuing Posted 2017-10-23 10:10
………………

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走走看看 Posted 2017-10-25 23:35
Last edited by 走走看看 2017-10-26 09:49回复 kuing、游客

好像在任一个顶点上,真操蛋!答案是D。

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