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a2+b2=1,b2+c2=2,c2+a2=2,则ab+bc+ca的最小值为( ...
a
2+b
2=1,b
2+c
2=2,c
2+a
2=2,则ab+bc+ca的最小值为( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687011_ST/0.png)
-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687011_ST/1.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687011_ST/2.png)
-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687011_ST/3.png)
C.-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687011_ST/4.png)
-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687011_ST/5.png)
D.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687011_ST/6.png)
+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687011_ST/7.png)
考点分析:
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![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131023212129778068721/SYS201310232121297780687008_ST/4.png)
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D.4
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