如图,正方形ACDE所在的平面与平面ABC垂直,M是CE和AD的交点,AC⊥BC,且AC=BC.
(Ⅰ)求证:AM⊥平面EBC;
(Ⅱ)求直线AB与平面EBC所成的角的大小;
(Ⅲ)求二面角A-EB-C的大小.
考点分析:
相关试题推荐
某社区举办2011年西安世园会知识宣传活动,进行现场抽奖,抽奖规则是:盒中装有10张大小相同的精美卡片,卡片上分别印有“世园会会徽”或“长安花”(世园会吉祥物)图案,参加者从盒中一次抽取卡片两张,记录后放回.若抽到两张都是“长安花”卡即可获奖.
(Ⅰ)活动开始后,一位参加者问:盒中有几张“长安花”卡?主持人说:我只知道若从盒中抽两张都不是“长安花”卡的概率是
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886015_ST/0.png)
,求抽奖者获奖的概率;
(Ⅱ)现有甲、乙、丙、丁四人每人抽奖一次,用ξ表示获奖的人数,求ξ的分布列及Eξ.
查看答案
已知函数f(x)=Asin(ωx+φ),(A>0,ω<0,|φ|<
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886014_ST/0.png)
)的部分图象如图所示.
(Ⅰ)求函数f(x)的解析式;
(Ⅱ)当g(x)=f(x)-2cos2x时,如何由函数y=sinx的图象通过适当的变换得到函数y=g(x)的图象,写出变换过程.
查看答案
出以下命题其中正确的命题有
(只填正确命题的序号).
①非零向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/0.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/1.png)
满足
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/2.png)
⊥
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/3.png)
,则|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/4.png)
+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/5.png)
|=|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/6.png)
-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/7.png)
|
②
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/8.png)
•
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/9.png)
>0,是
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/10.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/11.png)
的夹角为锐角的充要条件;
③将y=lg(x-1)函数的图象按向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/12.png)
=(-1,0)平移,得到的图象对应的函数为y=lgx;
④在△ABC中,若(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/13.png)
+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/14.png)
)•(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/15.png)
-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024183226500488673/SYS201310241832265004886013_ST/16.png)
)=0,则△ABC为等腰三角形.
查看答案
举行的数学竞赛中,全体参赛学生的竞赛成绩近似服从正态分布N(70,100),已知成绩在90分以上(含90分)的学生有12名,若Φ(2)=0.9772,则此次参赛生总人数约为
.
查看答案
如图,若PA=PB,∠APB=2∠ACB,AC与PB交于点D,且PB=4,PD=3,则AD•DC=
.
查看答案