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设实数x,y满足条件若目标函数z=ax+by(a>0,b>0)的最大值为12,则...
设实数x,y满足条件
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若目标函数z=ax+by(a>0,b>0)的最大值为12,则
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的最小值为( )
A.
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B.
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C.
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D.4
考点分析:
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按下列程序框图来计算:
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如果输入的x=5,应该运算( )次才停止.
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已知锐角α满足
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,则sin2α等于( )
A.
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B.
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C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124117571498218/SYS201310251241175714982004_ST/3.png)
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某空间几何体的三视图如图所示,该空间几何体的体积是( )
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D.
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下列说法正确的有( )个
①“
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”是“θ=30°”的充分不必要条件
②若命题p:∃x∈R,x
2-x+1=0,则¬p:∀x∈R,x
2-x+1≠0
③命题“若a=0,则ab=0”的否命题是:“若a≠0,则ab≠0”
④已知a,b∈R
+,若log
3a>log
3b,则
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.
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C.2
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