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用反证法证明命题“如果a>b>0,那么a2>b2”时,假设的内容应是( ) A....
用反证法证明命题“如果a>b>0,那么a2>b2”时,假设的内容应是( )
A.a2=b2
B.a2<b2
C.a2≤b2
D.a2<b2,且a2=b2
考点分析:
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“用反证法证明命题“如果x<y,那么x
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<y
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”时,假设的内容应该是( )
A.x
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=y
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B.x
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<y
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C.x
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=y
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且x
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<y
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D.x
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或x
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>y
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![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025123733327783782/SYS201310251237333277837021_ST/images0.png)
如图,平行四边形ABCD中,M是DC的中点,N在线段BC上,且NC=2BN.已知
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=
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,
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=
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,试用
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,
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表示
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和
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.
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,且
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,求tanB.
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