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已知A,B,C为平面上不共线的三点,若向量,,且•,则•等于( ) A.-2 B...
已知A,B,C为平面上不共线的三点,若向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230003195488253/SYS201311012300031954882003_ST/0.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230003195488253/SYS201311012300031954882003_ST/1.png)
,且
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230003195488253/SYS201311012300031954882003_ST/2.png)
•
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230003195488253/SYS201311012300031954882003_ST/3.png)
,则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230003195488253/SYS201311012300031954882003_ST/4.png)
•
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101230003195488253/SYS201311012300031954882003_ST/5.png)
等于( )
A.-2
B.2
C.0
D.2或-2
考点分析:
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