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已知各项均为正数的等比数列{an},a1a2a3=5,a7a8a9=10,则a4...
已知各项均为正数的等比数列{a
n},a
1a
2a
3=5,a
7a
8a
9=10,则a
4a
5a
6=( )
A.
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B.7
C.6
D.
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考点分析:
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,,则cos(π-α)的值为( )
A.
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B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102354187817446/SYS201311031023541878174000_ST/2.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102354187817446/SYS201311031023541878174000_ST/3.png)
D.-
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已知函数
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,且在
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上的最大值为
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,
(1)求函数f(x)的解析式;
(2)判断函数f(x)在(0,π)内的零点个数,并加以证明.
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已知函数f(x)=Asin(ωx+φ)(x∈R,ω>0,0<φ<
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)的部分图象如图所示.
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(Ⅱ)求函数g(x)=f(x-
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)-f(x+
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)的单调递增区间.
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已知函数f(x)=ax
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(1)求a,b,c的值;
(2)求f(x)在[-3,3]上的最小值;
(3)求函数f(x)在x=1处的切线方程.
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在△ABC中,内角A,B,C所对的边分别为a,b,c,已知sinB(tanA+tanC)=tanAtanC.
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(Ⅱ)若a=1,c=2,求△ABC的面积S.
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