题目内容
平面上点P与不共线三点A、B、C满足关系式:![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/0.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/1.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/2.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/3.png)
A.P在CA上,且
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/4.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/5.png)
B.P在AB上,且
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/6.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/7.png)
C.P在BC上,且
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/8.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_ST/9.png)
D.P点为△ABC的重心
【答案】分析:将
+
+
=
中的
移向,再化简整理得出
=2
,所以
与
共线,P在CA上.
解答:解:将
+
+
=
移向得:
+
=
-
,即:
+
=
+
=
,再移向得
=2
,
与
共线,P在CA上.
故选A.
点评:本题考查向量加法的几何运算,向量共线的判断,将原关系式移向,再化简整理得出
=2
是关键.
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/0.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/1.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/2.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/3.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/4.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/5.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/6.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/7.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/8.png)
解答:解:将
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/9.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/10.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/11.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/12.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/13.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/14.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/15.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/16.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/17.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/18.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/19.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/20.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/21.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/22.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/23.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/24.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/25.png)
故选A.
点评:本题考查向量加法的几何运算,向量共线的判断,将原关系式移向,再化简整理得出
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/26.png)
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131024183441842385543/SYS201310241834418423855012_DA/27.png)
![](http://thumb.zyjl.cn/images/loading.gif)
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