题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-58541.png)
(1)若AA1=2,求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-23073.png)
(2)若AA1=3,求二面角C1—BD—C的余弦值.
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-95823.png)
解析
(1)因为
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-83355.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-12041.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
(2)利用三垂线定理,先作出二面角,然后借助于三角形的边角的关系得到结论。
(1)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-83355.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-12041.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-83355.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-13140.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-24077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033754-58868.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033754-34838.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-24077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033754-43303.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-24077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-23073.png)
(2)过点C作
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033754-13204.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033754-47065.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-24077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033755-28264.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033752-30221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033754-13204.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033754-34838.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-24077.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033755-39241.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033755-60193.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033756-14704.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033756-27598.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033756-39881.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033756-49289.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033756-91960.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033753-95823.png)
核心考点
试题【(本题满分14分)如图,三棱柱ABC—A1B1C1中,AA1面ABC,BCAC,BC=AC=2,D为AC的中点。(1)若AA1=2,求证:;(2)若AA1=3,】;主要考察你对向量与空间位置关系等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033746-14442.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033746-98302.png)
A.若![]() ![]() |
B.若![]() ![]() |
C.若![]() ![]() |
D.若![]() ![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033737-63035.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033737-72660.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033737-67641.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033737-87505.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033737-79126.png)
(1)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033737-27349.png)
(2)求二面角
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033738-11291.png)
如图所示, 四棱锥P-ABCD的底面是边长为1的正方形,PA^CD,PA = 1, PD=,E为PD上一点,PE = 2ED.
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033726-47745.png)
(Ⅰ)求证:PA^平面ABCD;
(Ⅱ)求二面角D-AC-E的余弦值;
(Ⅲ)在侧棱PC上是否存在一点F,使得BF // 平面AEC?若存在,指出F点的位置,并证明;若不存在,说明理由.
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033718-97656.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033718-61372.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033718-86820.png)
(Ⅰ)试证:CD
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033718-97656.png)
(Ⅱ)设PA=k·AB,且二面角E-BD-C的平面角大于
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033718-13645.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033705-61645.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033705-32370.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033705-26194.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033705-29881.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033705-50556.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033706-22330.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033706-16809.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033706-30496.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033706-22330.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033706-97063.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033707-68100.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106033706-22330.png)
A.![]() | B.![]() | C.![]() | D.![]() |
最新试题
- 1如图所示,在⊙O内有折线OABC,其中OA=8,AB=12,∠A=∠B=60º,则BC的长为
- 2如果函数y=tan(x+φ)的图象经过点(π3, 0),那么φ可以是( )A.-π3B.-π6C.π6D.π3
- 3动物细胞的基本结构包括[ ]A.细胞壁、细胞质、细胞核 B.细胞膜、细胞核、细胞质 C.细胞膜、细胞
- 42009年10月31日,中国科学界“两弹一星”元勋 ________ 逝世。[ ]A.季羡林 B.阿沛·阿旺晋美
- 5— Must I feed the goldfish now? — No, you ______. But you mu
- 6综合性学习。 (10分)“世界充满爱!”世界上有爱的地方,就会有迷人的风景,就会有感人的故事,就会有萌动的情怀。亲爱的同
- 7阅读下面这首散曲,回答后面问题。【双调】雁儿落·带过得胜令吴西逸春花闻杜鹃,秋月看归雁。人情薄似云,风景疾如箭。留下买花
- 8为提高自信心,在平时的学习、工作和生活中,要善于发挥自己的优势,多创造成功的记录,长自己的志气;切不可张扬自己的弱点、缺
- 9阅读下面的文字,完成后面问题。诺耶夫花园(俄)帕乌斯托夫斯基有时候我也有空闲的日子。于是我一清早就走出家门,步行穿过全城
- 10设,,,则的大小关系是( )A.B.C.D.
热门考点
- 1阅读理解。 Kate is an English girl. She has two brothers,but
- 2世界近代史主要是资本主义制度在西方产生、确立、发展并向整个世界扩张的历史。一般认为它有两条主要发展线索:一条是资本主义制
- 3(5分)下列五种物质中,①H2O ②CO2③Na2O2 ④NaOH ⑤NaBr,只存在共价键的是__________,只
- 4封建社会皇帝与丞相之间容易产生矛盾,从汉至元历代皇帝采取的限制相权的措施包括 ( )
- 5若函数y=ax-2(a>0,且a≠1)的图象恒过点P,则点P的坐标为( )A.(3,0)B.(-1,0)C.(0,-1
- 6已知△ABC中,,,,那么等于_______________
- 7善于归纳知识,利于培养素质。小林同学整理的下列内容有错误的是 [ ]A.除杂的方法B.化学物质中的“三”C.安全
- 8本学期我们学习的名著是前苏联作家奥斯特洛夫斯基的_________________,作品的主人公是___________
- 9完形填空。 Making friends is a skill.Like most skills, it imp
- 10(7分)冬天,小方陪妈妈去医院打点滴,发现护士往输液管上放了一个纸包(如图所示),经询问得知它可以温暖输入人体中的液体。