如图,在四棱锥
中,底面
是正方形,侧面QAD是正三角形,侧面
底面
,M是QD的中点.
平面
;
(2)求侧面QBC与底面
所成二面角的余弦值;
(3)在棱QC上是否存在点N使平面
平面AMC成立?如果存在,求出
,如果不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55c6caa0455442437177ab9b995df37b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb11df029afb11e4233989b1338cb3a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d0edb1508fc95765f3bb316bcb5252d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c550269f3199038726f55cbd281c13a.png)
(2)求侧面QBC与底面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(3)在棱QC上是否存在点N使平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a2e866037fb17d7fb74b462ef2f34d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6525116388ec2bf0e2828bdc3cc5d3b9.png)
22-23高一下·吉林长春·期末 查看更多[10]
吉林省长春市实验中学2022-2023学年高一下学期期末数学试题(已下线)第10章 空间直线与平面(压轴题专练)-2023-2024学年高二数学单元速记·巧练(沪教版2020必修第三册)(已下线)第八章 立体几何初步(提升卷)-重难点突破及混淆易错规避(人教A版2019必修第二册)(已下线)6.5.2平面与平面垂直-【帮课堂】(北师大版2019必修第二册)(已下线)高一下学期期末复习解答题压轴题二十四大题型专练(2)-举一反三系列(人教A版2019必修第二册)(已下线)高一下学期期末数学试卷(巩固篇)-举一反三系列(人教A版2019必修第二册)江苏省宿迁市泗阳县实验高级中学2023-2024学年高一下学期第二次调研测试(5月)数学试题安徽省安庆市第一中学2023-2024学年高一下学期5月同步测试数学试卷河南省信阳市浉河区信阳高级中学2023-2024学年高一下学期6月月考数学试题西安市交大附中2023—2024学年高一下学期第二次月考数学试题
更新时间:2023-07-31 21:41:03
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相似题推荐
解答题-证明题
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【推荐1】《九章算术》中,将底面为长方形且有一条侧棱与底面垂直的四棱锥称之为阳马,将四个面都为直角三角形的四面体称之为鳖臑.
如图,在阳马
中,侧棱
底面
,且
,过棱
的中点
,作
交
于点
,连接 ![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b9239dd73df715a39ae6f3f69f14a92.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/10/fdfbbd24-8548-41c1-8788-6c0994e50143.png?resizew=175)
(Ⅰ)证明:
.试判断四面体
是否为鳖臑,若是,写出其每个面的直角(只需写
出结论);若不是,说明理由;
(Ⅱ)若面
与面
所成二面角的大小为
,求
的值.
如图,在阳马
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37e2267c84394668eff2e9f5918de4fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a4a6a1e70241d600bc6c104313eac61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b9239dd73df715a39ae6f3f69f14a92.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/10/fdfbbd24-8548-41c1-8788-6c0994e50143.png?resizew=175)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/017797398acdf601fd6f40b1e20e8751.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfc50ecfa45216f8d098662452cf8d08.png)
出结论);若不是,说明理由;
(Ⅱ)若面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134ef0b1a2669a09f05bd4dc2496f706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac1a63ab608517bb10aa036783dfb51f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54625f5af5647c5dad88675510c4711b.png)
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【推荐2】在直角梯形ABCD中,
,
,∠ABC=90°(如图1).把△ABD沿BD翻折,使得二面角A-BD-C的平面角为
(如图2),M、N分别是BD和BC中点.
表示),详细说明理由;
(2)若P、Q分别为线段AB与DN上一点,使得
,令PQ与BD和AN所成的角分别为
和
,求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4adf90a8c2b29334cdc5aa5b554991f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cbd8599cee48d867a73477d60b1f62f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
(2)若P、Q分别为线段AB与DN上一点,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8dc43c691611aec272edad5aa7e2fe3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25f64fa38725c136504f723019a18dc5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e93fa313adc4ac7608ba9449fd755212.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d42cd1f65b49da85d8563e1dca540d4.png)
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【推荐1】如图,直三棱柱
的底面是边长为2的正三角形,侧棱
,
是线段
的延长线上一点,平面
分别与
相交于
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/cbbc650f-d7b6-47f3-8830-9a338c8c8d87.png?resizew=169)
(1)求证:
平面
;
(2)求当
为何值时,平面
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/986ba572d8373df48c996f8c8611498c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f4aca5534bce25acaeb7379deed8f8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9506adf67d4563138dfeb21365b1ba22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/cbbc650f-d7b6-47f3-8830-9a338c8c8d87.png?resizew=169)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcf19a7f0dd0cdf59516ae585025110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10fc7991ea17d54ff5f4445ac5699463.png)
(2)求当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fb26d84907c923278ac4626a9d58947.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10fc7991ea17d54ff5f4445ac5699463.png)
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【推荐2】已知在直三棱柱
中,
,
为
的中点,在线段
上是否存在一点
,使得平面
平面
,若存在,请求出CN与
的比值;若不存在,说明理由;
(2)将两块形状与该直三棱柱完全相同的木料按如下图所示两种方案沿阴影面进行切割,把木料一分为二,留下体积较大的一块木料.根据你所学的知识,请判断采用哪一种方案会使留下的木料表面积较大,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2902d52b4fd9e2542207339b6d9d87b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c1204a39f20cea0d6bfec8e72d07a62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a70691e3884c6b35eace61575b12831.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b4c0fdc09d58a130e5b9155cde03ce8.png)
(2)将两块形状与该直三棱柱完全相同的木料按如下图所示两种方案沿阴影面进行切割,把木料一分为二,留下体积较大的一块木料.根据你所学的知识,请判断采用哪一种方案会使留下的木料表面积较大,并说明理由.
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【推荐3】如图,三棱柱
中,
平面
,
,
,
,以
,
为邻边作平行四边形
,连接
和
.
![](https://img.xkw.com/dksih/QBM/2014/5/12/1571712601071616/1571712607068160/STEM/625373d6-e844-43c7-a40f-acb2883d026f.png?resizew=193)
(Ⅰ)求证:
平面
;
(Ⅱ)求直线
与平面
所成角的正弦值;
(Ⅲ)线段
上是否存在点
,使平面
与平面
垂直?若存在,求出
的长;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7ad3a578f403b9e6b97fa2dc955fc11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92535536bd3c2761724fd058427f95a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e75d14708e6aa1404477db9d7e3166f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2eb89294b31ffdd2680b4361e8994d7.png)
![](https://img.xkw.com/dksih/QBM/2014/5/12/1571712601071616/1571712607068160/STEM/625373d6-e844-43c7-a40f-acb2883d026f.png?resizew=193)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4ac809549102844f24d73a5bfdf2464.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
(Ⅱ)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cee3d1518e197f7f25c341da6b1e3483.png)
(Ⅲ)线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cee3d1518e197f7f25c341da6b1e3483.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ee076fe7dbca5616c4e8a6869a355f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
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【推荐1】在正三角形
中,E、F、P分别是
、
、
边上的点,满足
(如下左图).将
沿
折起到
的位置,使二面角
成直二面角,连结
、
(如下右图).
平面
;
(2)求二面角
的大小(用反三角函数表示).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.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/c06ee44206d4e110610bc412f11f2ab5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb2d555062f34d5a74f6d47da4ea8888.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc14ed237a4bcc35cbd1f5f1321b3718.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d0ff310aabd2282b539537ebed3f788.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4525c00ed908bed8ba8d353e747a858.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24fac8b38a9cf7602391f6d6ca933bd2.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8097ceec369f4de5071a58290ce6e7e9.png)
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【推荐2】在三棱柱
中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01d3c678487171bdd647403a2b56a01c.png)
点
为棱
的中点,点
是线段
上的一动点,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb008257b3266ecb9fe74788a245cdb8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/13/9ce95078-8927-4e78-a643-d11239cae652.png?resizew=208)
(1)证明:
;
(2)求平面
与平面
所成的二面角的正弦值;
(3)设直线
与平面
、平面
、平面
所成角分别为
求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01d3c678487171bdd647403a2b56a01c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce8be010cdb9fe9bb2bdc097a04f8e1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b68df477b3ee45ac0f725db00d465a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb008257b3266ecb9fe74788a245cdb8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/13/9ce95078-8927-4e78-a643-d11239cae652.png?resizew=208)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88a40737954d2edc87e6046a1c80e904.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f96c673a2381f118ea2d3efc0bca1f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31e53b212640dadf751ef7f65a78a209.png)
(3)设直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b1ec05e3cec27677ded7b4aecaa62d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f96c673a2381f118ea2d3efc0bca1f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9b7b7793d29d66dfdd89e7a6564a35c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d473a184e98a5f60947009da07dbe8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a872b4a59655457dda0669c4461edc66.png)
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【推荐3】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)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
名校
【推荐1】如图,在四棱锥
中,底面为边长为2的菱形,
为正三角形,且平面
平面
,
为线段
中点,
在线段
上.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/27/972ec265-478c-4d08-be79-881cefb70542.png?resizew=193)
(1)当
是线段
中点时,求证:
平面
;
(2)当
时,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d25011343f362d9ba9a1733f64b7db0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/27/972ec265-478c-4d08-be79-881cefb70542.png?resizew=193)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30067b7b236d17af8a462f96a58d11bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af68a7bf0da4f7c6f739d2e2461ad9b7.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21554ae727c34081e967cf8bb3e43f71.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90985b4cec465c6c3710ffe7e0ed9fae.png)
您最近一年使用:0次
解答题-问答题
|
较难
(0.4)
【推荐2】如图,四棱柱
的底面
为矩形,
,
为
中点,平面
平面
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/16/0f0acce1-982e-4d04-8450-66c49e7c3482.png?resizew=261)
(1)证明:
平面
;
(2)求平面
与平面
的夹角的余弦值.
![](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/1b929269c53a44907dba8ee298a0a522.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a45953045e613b97eeee15ac188ae2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd0fd39907f1fb7c9bee6f00ca56a60a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/16/0f0acce1-982e-4d04-8450-66c49e7c3482.png?resizew=261)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4890e58791814622b87c4d60ea971f54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20fc4fbd9390e2a5200920910abc63b2.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edc9ffc43a56921fe79f8602636b8b0f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db550a1768436a7cf2bcc62eb3d7cc63.png)
您最近一年使用:0次
解答题-问答题
|
较难
(0.4)
【推荐3】已知四边形ABCD为菱形,
,
,沿着AC将它折成如图所示的直二面角
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d9943f735c2a464a42b61a50b2b7856.png)
(1)求CE;
(2)求平面CDE与平面ABC所成的二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8a7b5adfcac0f46a4cd19da4ebb4a2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/970bd8c6012979f91c4b370fad352d47.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f0ac3005d5ecd6d4cea0ce99a47ef3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d9943f735c2a464a42b61a50b2b7856.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/15/5ffe4e1d-f0be-49e7-9660-7686097a21fa.png?resizew=139)
(1)求CE;
(2)求平面CDE与平面ABC所成的二面角的余弦值.
您最近一年使用:0次