1 . 三棱锥
中,底面
是等腰直角三角形,
,且
为
中点,如图.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/8/3406a918-97d1-49ce-9566-07a5931e59a4.png?resizew=175)
(1)求证:平面
平面
;
(2)若二面角
的大小为
,求
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7df6d51738ac1bc8b9530ea4a55745c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e811de9e45a4a5bcd79b2280e1a05eef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/124da312360cbb0bb6cf7266191e1066.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/8/3406a918-97d1-49ce-9566-07a5931e59a4.png?resizew=175)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a57bcc0265d1e30b5b0f9216fef9522.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
(2)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca6d1c5eace748465b2dad5065f5111c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
您最近一年使用:0次
2019-04-30更新
|
1229次组卷
|
4卷引用:青海省西宁市2020届高三复习检测(二)数学试题
青海省西宁市2020届高三复习检测(二)数学试题【市级联考】广东省湛江市2019届高三高考模拟测试(二)理科数学试题(已下线)专题02 从空间到平面,助力破解立体几何问题 (第四篇)-2020高考数学压轴题命题区间探究与突破甘肃省天水市第一中学2018-2019学年高二下学期第二学段考试数学(理)试题
解题方法
2 . 如图,在各棱长均为4的直四棱柱
中,底面
为菱形,
,
为棱
上一点,且
.
![](https://img.xkw.com/dksih/QBM/2018/2/13/1881679759695872/1884348469927936/STEM/64ee98d2-d146-485b-a54c-4bef1bd1712f.png?resizew=195)
(1)求证:平面
平面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/694fc1d576562f85acd2f157818f97cd.png)
![](https://img.xkw.com/dksih/QBM/2018/2/13/1881679759695872/1884348469927936/STEM/64ee98d2-d146-485b-a54c-4bef1bd1712f.png?resizew=195)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8dc6db50a9709c3f4d84eee7bdf1250.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2bf9ef324f1289e205e29fed105c38e.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53eab3d46050258e079f1bcfced25c0e.png)
您最近一年使用:0次
2018-02-17更新
|
355次组卷
|
2卷引用:青海省西宁市大通回族土族自治县2021届高三三模数学(理)试题
3 . 如图,四边形
是正四棱柱
的一个截面,此截面与棱
交于点
,
,其中
分别为棱
上一点.
(1)证明:平面
平面
;
(2)
为线段
上一点,若四面体
与四棱锥
的体积相等,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b54a965aa682d6d2aa484a43d4941c91.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd694ad3a4733c7c84aaa7946aeea4de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b094e639c2b31dc54b1b3e6456e77843.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79ebbdaca2dccbe2b04d30b2e7647c70.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c49eedafe3b03a81c9ca2ab75cbacb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/845b14c775d9e390548f0d7e2914c2af.png)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a38d46c073a39ba804abcf509fcbf473.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b54a965aa682d6d2aa484a43d4941c91.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/586f3bc416371da2f99f4af85ecf6e8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4138c7eeeca7c3a6abffdc9130bd83f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07377d977ef6a8f518b3004564544e5b.png)
![](https://img.xkw.com/dksih/QBM/2017/12/5/1832060792750080/1834248951848960/STEM/32b38b10-2f7c-4651-b44b-20c2f26ff2eb.png?resizew=191)
您最近一年使用:0次
2017-12-08更新
|
322次组卷
|
3卷引用:青海省西宁市大通回族土族自治县2021届高三三模数学(文)试题
4 . 已知四棱锥
的底面是菱形.
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/2013/6/17/1571245934362624/1571245940064256/STEM/593a827e5beb4d219c9871c8233dbdf1.png)
(1)求证:
∥平面
;
(2)求证:平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6153163fecdf3f410411048428ccaef5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32d0710321d97361e5782124bbf7f0c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://img.xkw.com/dksih/QBM/2013/6/17/1571245934362624/1571245940064256/STEM/593a827e5beb4d219c9871c8233dbdf1.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba9008f244e609ad267e10b8861c8254.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
您最近一年使用:0次
2016-12-02更新
|
1680次组卷
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5卷引用:2013届青海省西宁五中片区高三大联考文科数学试卷
(已下线)2013届青海省西宁五中片区高三大联考文科数学试卷(已下线)2010-2011学年北京东城区度综合练习(一)高三数学 (文科)北京昌平一中2016-2017学年高二上学期期中考试数学试题甘肃省临夏州临夏中学2018-2019学年高一上学期第二次月考数学试题安徽省合肥市六校联考2020-2021学年高一下学期期末数学试题