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已知点(x,y)是不等式组表示的平面区域内的一个动点,且目标函数z=2x+y的最...
已知点(x,y)是不等式组
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表示的平面区域内的一个动点,且目标函数z=2x+y的最大值为7,最小值为1,则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103101051457280464/SYS201311031010514572804006_ST/1.png)
的值为( )
A.2
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103101051457280464/SYS201311031010514572804006_ST/2.png)
C.-2
D.-1
考点分析:
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,其中
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是非零向量,则“函数f(x)的图象是一条直线”的充分条件是( )
A.
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B.
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C.
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D.
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已知数列{a
n}为等差数列,{b
n}为等比数列,且满足:a
1000+a
1012=π,b
1b
14=-2,则
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=( )
A.1
B.-1
C.
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D.
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C.
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D.
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B.
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D.
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2-2x+1<0的解集非空的一个必要而不充分条件是( )
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B.a<0
C.0<a<1
D.a≤1
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