名校
1 . 1611年,约翰内斯·开普勒提出了“没有任何装球方式的密度比面心立方与六方最密堆积要高”的猜想.简单地说,开普勒猜想就是对空间中如何堆积最密圆球的解答.2017年,由匹兹堡大学数学系教授托马斯·黑尔斯(Thomas Hales)带领的团队发表了关于开普勒猜想证明的论文,给这个超过三百年的历史难题提交了一份正式的答案.现有大小形状都相同的若干排球,按照下面图片中的方式摆放(底层形状为等边三角形,每边4个球,共4层),这些排球共__________ 个,最上面球的球顶距离地面的高度约为__________
(排球的直径约为
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9efa9fbcfb9595e2f031aa691db4564b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d2eb8ac733873fb3e728399ac856f16.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/8/0c87873d-c7f2-4a40-aad6-fc2f10261701.png?resizew=133)
您最近一年使用:0次
2020-04-24更新
|
427次组卷
|
2卷引用:2020届甘肃省第一次高考诊断考试理科数学试题
2 . 如图,在四棱锥P﹣ABCD中,底面ABCD是菱形,∠BAD=60°,边长为4的正△PAD所在平面与平面ABCD垂直,点E是AD的中点,点Q是侧棱PC的中点.
(2)求证:PA∥平面BDQ;
(3)在线段AB上是否存在点F,使直线PF与平面PAD所成的角为30°?若存在,求出AF的长,若不存在,请说明理由?
(2)求证:PA∥平面BDQ;
(3)在线段AB上是否存在点F,使直线PF与平面PAD所成的角为30°?若存在,求出AF的长,若不存在,请说明理由?
您最近一年使用:0次
3 . 如图,四棱锥
的底面
是平行四边形,
底面
,
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/7d5584d0-f77b-4ae4-a21a-3675cb6414ff.png?resizew=170)
(1)求证:平面
平面
;
(2)若点
分别为
上的点,且
,在线段
上是否存在一点
,使得
平面
;若存在,求出三棱锥
的体积;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/491c3a4f72b84ebadd28b90711435adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26d4e574c9d139615d991a168cfbf63b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/7d5584d0-f77b-4ae4-a21a-3675cb6414ff.png?resizew=170)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78a3fd5284e160896f07ce367645fd04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7366da07065712da11602f4afce8cbed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a504ffd2e4b994a4d1425049a19c6c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02438f0423acd0ff2dfa5ffb6abf143f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45d492a2248463e0c0199a25d0f76d23.png)
您最近一年使用:0次
2019-12-08更新
|
475次组卷
|
5卷引用:云南省师范大学附属中学2018届高三适应性月考卷(二)(文)数学试题
云南省师范大学附属中学2018届高三适应性月考卷(二)(文)数学试题(已下线)专题8.5 直线、平面垂直的判定及其性质(练)-浙江版《2020年高考一轮复习讲练测》(已下线)专题8.5 直线、平面垂直的判定及性质(精练)-2021年新高考数学一轮复习学与练(已下线)专题8.5 直线、平面垂直的判定及性质(练)-2021年新高考数学一轮复习讲练测(已下线)专题8.5 直线、平面垂直的判定及性质(练)- 2022年高考数学一轮复习讲练测(新教材新高考)
名校
解题方法
4 . 设三棱锥
的每个顶点都在球
的球面上,
是面积为
的等边三角形,
,
,且平面
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/22/96255708-36bb-4b7c-8821-0f3aa5185494.png?resizew=176)
(1)确定
的位置(需要说明理由),并证明:平面
平面
.
(2)与侧面
平行的平面
与棱
,
,
分别交于
,
,
,求四面体
的体积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53502463cc76201000e02df314e58769.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adbd3e8cf8325999cde03adf845d3dd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/615fc8790237a1b09af51d6bcad6b595.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/22/96255708-36bb-4b7c-8821-0f3aa5185494.png?resizew=176)
(1)确定
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7392e9e2da5a0e9ecab0f79992656328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)与侧面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c10f93679abcee21bacd92c3b1552a0e.png)
您最近一年使用:0次
2020-02-18更新
|
891次组卷
|
4卷引用:2020届吉林省通化市梅河口市第五中学高三上学期期末数学(文)试题
2020届吉林省通化市梅河口市第五中学高三上学期期末数学(文)试题2020届吉林省实验中学高三第一次检测考试数学(文)试题(已下线)专题04 立体几何-2020年高三数学(文)3-4月模拟试题汇编(已下线)文科数学-6月大数据精选模拟卷04(新课标Ⅲ卷)(满分冲刺篇)
5 . 如图,四棱锥
中,
底面
,点
在线段
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/8952a610-ed36-4cfd-8872-b89dc98335f9.png?resizew=198)
(1)求证:
平面
;
(2)若
,求四棱锥
的体积;
(3)若
,作
于F,作
于![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d27546408b3fc40aed7d7d66e35e5561.png)
,当
变化时,求三棱锥
体积的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77056009e9e7d6df3e363a5b3b938f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a763381e4a9e6ac9d9c1df51122570f8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/8952a610-ed36-4cfd-8872-b89dc98335f9.png?resizew=198)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44b190c8d3d7d7d0e6e959e8a52eae90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f21153660360f36cf3dd1768845514be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bae7599ad243c12d94325ad917f0a44.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8cc33ee7afea61f57d8c5dc43e79596.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a33a80f99e4881a1882389996b6aa36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d27546408b3fc40aed7d7d66e35e5561.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cfd2db87465dec3ea9683840a326dba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69ca2a6452530eb88899803f94b75540.png)
您最近一年使用:0次
名校
6 . 用一个平面去截直立放置的圆柱,得圆柱的下半部分如图,其中
为截面的最低点,
为截面的最高点,
为线段
中点,
为截面边界上任意一点,作
垂直圆柱底面于点
,
垂直圆柱于底面于点
,
垂直圆柱于底面于点
,圆柱底面圆心为
.已知
为底面直径,
在以
为直径的圆周上,
垂直底面,
,
,
,以
为原点,
为
轴正方向,圆柱底面为
平面,
为
轴正方向建立空间直角坐标系,设点
.
![](https://img.xkw.com/dksih/QBM/2019/11/30/2345237225152512/2346704160530432/STEM/bd60d595dc0349cbb253f9582963b433.png?resizew=189)
![](https://img.xkw.com/dksih/QBM/2019/11/30/2345237225152512/2346704160530432/STEM/ccdc4ae8e84644b7ac0bac7181b5ad12.png?resizew=485)
(1)求点
的坐标,并求出
与
之间满足的关系式;
(2)三视图是解决立体几何问题时的有效工具,将圆柱下半部分在
平面上的投影作为主视图,在
平面上的投影作为俯视图;在方框中作出主视图,并说明理由;再求出左视图所围区域的面积;
(3)判断截面的边界是什么曲线,并证明.再指出截面的面积(不需要证明)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97c01fdc7bc471af0b264a04aef0823e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/893ff0f9b64c66312c37cb7ce90c351d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3369e0ea90e8d5cf4b6b3c45c0fd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92535536bd3c2761724fd058427f95a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cc416a5b8dc234628e7475387888d82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/570f8b295ee0c7c60e6fe1dbf054ff52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4195334905e2f190f958dbf5951456f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ee31829d0d4d5f779a957d7df8058ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaf3369e0ea90e8d5cf4b6b3c45c0fd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e81e59019989b7dc2fb59b037ef6e010.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed6f3500ae262485ca77ac00d8c4c247.png)
![](https://img.xkw.com/dksih/QBM/2019/11/30/2345237225152512/2346704160530432/STEM/bd60d595dc0349cbb253f9582963b433.png?resizew=189)
![](https://img.xkw.com/dksih/QBM/2019/11/30/2345237225152512/2346704160530432/STEM/ccdc4ae8e84644b7ac0bac7181b5ad12.png?resizew=485)
(1)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
(2)三视图是解决立体几何问题时的有效工具,将圆柱下半部分在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7d96461d2b3421aed548b754637ca8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ee31829d0d4d5f779a957d7df8058ab.png)
(3)判断截面的边界是什么曲线,并证明.再指出截面的面积(不需要证明)
您最近一年使用:0次
名校
7 . 如图,
是底面边长为1的正三棱锥,
分别为棱长
上的点,截面
底面
,且棱台
与棱锥
的棱长和相等.(棱长和是指多面体中所有棱的长度之和)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/061c79b9-f048-4da4-9014-8ac87085db94.png?resizew=163)
(1)证明:
为正四面体;
(2)若
,求二面角
的大小;(结果用反三角函数值表示)
(3)设棱台
的体积为
,是否存在体积为
且各棱长均相等的直平行六面体,使得它与棱台
有相同的棱长和?若存在,请具体构造出这样的一个直平行六面体,并给出证明;若不存在,请说明理由.
(注:用平行于底的截面截棱锥,该截面与底面之间的部分称为棱台,本题中棱台的体积等于棱锥
的体积减去棱锥
的体积.)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/927456b0989846a2f1573844bbaa2105.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19bb1063e139610045f3bca5ca0b2766.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94b85a145f7005af0ed86afa0b99ab32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8783bc74553bf44b61d999a0e4144bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/061c79b9-f048-4da4-9014-8ac87085db94.png?resizew=163)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7fcbd32d874c0095b0c993efdc1e7c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab6d47edbcc2ae6efcfd7f28e401e3e9.png)
(3)设棱台
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8783bc74553bf44b61d999a0e4144bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be54e84508decfcce6d2fcbe6c8c1a92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be54e84508decfcce6d2fcbe6c8c1a92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8783bc74553bf44b61d999a0e4144bb.png)
(注:用平行于底的截面截棱锥,该截面与底面之间的部分称为棱台,本题中棱台的体积等于棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16fd1bc6147d69777b26a35d48522f7e.png)
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2019-09-23更新
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1077次组卷
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6卷引用:上海市宝山区交大附中2018-2019学年高二下学期期中数学试题
上海市宝山区交大附中2018-2019学年高二下学期期中数学试题上海市交通大学附属中学2018-2019学年高二下学期期中数学试题人教B版(2019) 必修第四册 过关斩将 第十一章 立体几何初步 11.3~11.4 综合拔高练(已下线)专题4.4 空间直线与平面【压轴题型专项训练】-2020-2021学年高二数学下学期期末专项复习(沪教版)(已下线)期中真题必刷常考60题(22个考点专练)-【满分全攻略】2023-2024学年高二数学同步讲义全优学案(沪教版2020必修第三册)(已下线)期中真题必刷易错40题(17个考点专练)-【满分全攻略】2023-2024学年高二数学同步讲义全优学案(沪教版2020必修第三册)
8 . 如图,在四棱锥
中,四边形
是矩形,平面
平面
,点
、
分别为
、
中点,
.三棱锥
的体积
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/d4ddd046-a090-4d89-b37b-e0b65ab574e6.png?resizew=146)
(1)求证:
平面
;
(2)求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d02bd5cfe804460846423e77f72db10f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4da035673ef0edcfae6b72fb5e5ba34a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80672dda9430cb42b3136bcb1b67bbad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3c4506f3a97f941211d7e3e41df8ba0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1712e74c9af60c68f70c9ab452ee83c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65587af52415b8a65a2123d65d34dc93.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/d4ddd046-a090-4d89-b37b-e0b65ab574e6.png?resizew=146)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/073a88b42836fb88433679932b48ad03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7609a1407f1e965fc9f1235552dcf9e.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88929f4ba0851730d5f941d426b87548.png)
您最近一年使用:0次
18-19高二下·上海·期中
名校
9 . 平面图形很多可以推广到空间中去,例如正三角形可以推广到正四面体,圆可以推广到球,平行四边形可以推广到平行六面体,直角三角形也可以推广到直角四面体,如果四面体
中棱
两两垂直,那么称四面体
为直角四面体. 请类比直角三角形中的性质给出2个直角四面体中的性质,并给出证明.(请在结论
中选择1个,结论4,5中选择1个,写出它们在直角四面体中的类似结论,并给出证明,多选不得分,其中
表示斜边上的高,
分别表示内切圆与外接圆的半径)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/766565857d28617cc4c2a26ecf76ec24.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5332ae9dc9d9c4cff2ac5262714d899c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eabd5f3a86afe49dcd70571e2b96cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25dce64d610e7f309e414d9abe7ff2e3.png)
直角三角形![]() | 直角四面体![]() | |
条件 | ![]() | ![]() |
结论1 | ![]() | |
结论2 | ![]() | |
结论3 | ![]() | |
结论4 | ![]() | |
结论5 | ![]() |
您最近一年使用:0次
10 . 在如图所示的空间几何体中,平面
平面
,
与
是边长为
的等边三角形,
,
和平面
所成的角为
,且点
在平面
上的射影落在
的平分线上.
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/729a0642325f4332a3b246558ef4be65.png)
(Ⅰ)求证:
平面
;
(Ⅱ)求三棱锥
的体积
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/8d94cb312de14a2d8bb31b99bb188f79.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/d77cdc2af6ff40b28ddb2c5ebe188de5.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/d5504b6ac1c44c68b885d70e7d66b11c.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/4d883e04136943c6be22012e2abf2fb1.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/db5effdfa6c644b89d27007865bf3131.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/2f34d3e5d97140169ac2908e4fb06a63.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/5f0713cfaf6f4a4d8afaf829eb3b30dd.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/d77cdc2af6ff40b28ddb2c5ebe188de5.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/eb3b103a88544597b735ffeb9b7508cd.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/21591274be7448b0a7420679d57b88f0.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/d77cdc2af6ff40b28ddb2c5ebe188de5.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/2c4da7351f774a048fd419f4d0f568e0.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/729a0642325f4332a3b246558ef4be65.png)
(Ⅰ)求证:
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/68d869f0fde24661919c0ebd638c81fe.png)
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/d77cdc2af6ff40b28ddb2c5ebe188de5.png)
(Ⅱ)求三棱锥
![](https://img.xkw.com/dksih/QBM/2015/1/6/1571952773652480/1571952779616256/STEM/67fdcdd121b749849222e1ba16640420.png)
您最近一年使用:0次