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如图,在三棱锥S-ABC中,平面SAB⊥平面SBC,AB⊥BC,AS=AB,过A作AF⊥SB,垂足为F,点E,G分别是棱SA,SC的中点.求证:
(1)平面EFG∥平面ABC;
(2)BC⊥SA.
考点分析:
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已知
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315014_ST/0.png)
=(cosα,sinα),
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315014_ST/1.png)
=(cosβ,sinβ),0<β<α<π.(1)若|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315014_ST/2.png)
-
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|=
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,求证:
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⊥
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;(2)设c=(0,1),若
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315014_ST/7.png)
+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315014_ST/8.png)
=c,求α,β的值.
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在正项等比数列{a
n}中,
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,a
6+a
7=3,则满足a
1+a
2+…+a
n>a
1a
2…a
n的最大正整数n的值为
.
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在平面直角坐标系xOy中,设定点A(a,a),P是函数y=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315012_ST/0.png)
(x>0)图象上一动点,若点P,A之间的最短距离为2
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315012_ST/1.png)
,则满足条件的实数a的所有值为
.
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在平面直角坐标系xOy中,椭圆C的标准方程为
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315011_ST/0.png)
(a>b>0),右焦点为F,右准线为l,短轴的一个端点为B,设原点到直线BF的距离为d
1,F到l的距离为d
2,若d
2=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124332914831541/SYS201310251243329148315011_ST/1.png)
,则椭圆C的离心率为
.
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已知f(x)是定义在R上的奇函数.当x>0时,f(x)=x
2-4x,则不等式f(x)>x 的解集用区间表示为
.
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