已知△ABC的三内角A、B、C所对的边的长分别为a、b、c,设向量
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(1)求∠B;
(2)若
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ABC的面积.
考点分析:
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如图,在四棱锥P-ABCD中,底面ABCD是正方形,PD⊥底面ABCD,M、N分别为PA、BC的中点,且PD=AD=
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,CD=1
(1)求证:MN∥平面PCD;
(2)求证:平面PAC⊥平面PBD;
(3)求三棱锥P-ABC的体积.
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已知函数
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.
(1)求f(x)的最小正周期;
(2)若将f(x)的图象向右平移
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个单位,得到函数g(x)的图象,求函数g(x)在区间[0,π]上的最大值和最小值.
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已知数列{a
n}中,
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,则a
n=
.
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实数x,y满足不等式组
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232014_ST/0.png)
则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232014_ST/1.png)
的范围
.
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关于平面向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/0.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/1.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/2.png)
,有下列三个命题:
①若
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•
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/4.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/5.png)
•
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/6.png)
,则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/7.png)
=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/8.png)
、
②若
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/9.png)
=(1,k),
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/10.png)
=(-2,6),
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/11.png)
∥
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/12.png)
,则k=-3.
③非零向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/13.png)
和
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/14.png)
满足|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/15.png)
|=|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/16.png)
|=|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/17.png)
-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/18.png)
|,则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/19.png)
与
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+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101231405921723291/SYS201311012314059217232013_ST/21.png)
的夹角为60°.
其中真命题的序号为
.(写出所有真命题的序号)
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