如图,四棱锥
中,
平面
平面
.
![](https://img.xkw.com/dksih/QBM/2022/4/14/2958108894576640/2958549927542784/STEM/b86bb93e-3052-4040-869d-c3b45a77f745.png?resizew=259)
(1)若
为等边三角形,求证:
∥平面
;
(2)当四棱锥
的体积最大时,求二面角
的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce12b74f689d61d372993ff0cc6e1535.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21081b84313382e2a1821d43f3901350.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d992c5683a6c67f704275c2feee9ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90dbbd5b2fd0e7f1a69339f04cbfa5b6.png)
![](https://img.xkw.com/dksih/QBM/2022/4/14/2958108894576640/2958549927542784/STEM/b86bb93e-3052-4040-869d-c3b45a77f745.png?resizew=259)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f9dc427a01582ec222446b352d40ab0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2c3d2cba96f6f03520c0b3f6e4da03e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)当四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce12b74f689d61d372993ff0cc6e1535.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7fe3b229674fb062daaca049540b9b1.png)
更新时间:2022-04-15 09:28:08
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐1】已知直三棱柱
中,
,
,
.
![](https://img.xkw.com/dksih/QBM/2021/12/7/2867393608392704/2868877442506752/STEM/2dbb6858e68946e48247a7cc5cf2d1ec.png?resizew=132)
![](https://img.xkw.com/dksih/QBM/2021/12/7/2867393608392704/2868877442506752/STEM/7c2832dd27a5462f951b507436e5590f.png?resizew=223)
(1)若
为
的中点,证明:
平面
;
(2)将两块形状与该直三棱柱完全相同的木料按如图所示两种方案沿阴影面进行分割,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,并求出这个较大的表面积和说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/883fc5e3faf39829d60804b59deb1730.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d6baf49925a5bcb359b542d45067c81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92535536bd3c2761724fd058427f95a8.png)
![](https://img.xkw.com/dksih/QBM/2021/12/7/2867393608392704/2868877442506752/STEM/2dbb6858e68946e48247a7cc5cf2d1ec.png?resizew=132)
![](https://img.xkw.com/dksih/QBM/2021/12/7/2867393608392704/2868877442506752/STEM/7c2832dd27a5462f951b507436e5590f.png?resizew=223)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/547a4b438e2e6687c7cd55ea08bbaae2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0afb7e8ef610cb5588bd52755399921a.png)
(2)将两块形状与该直三棱柱完全相同的木料按如图所示两种方案沿阴影面进行分割,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,并求出这个较大的表面积和说明理由.
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【推荐2】如图,在直三棱柱
中,底面
是直角三角形,且
,
,其中
,
分别是
,
上的点且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/6/54101104-b394-4628-8192-03563c15682c.png?resizew=156)
(1)求证:MN
平面
;
(2)求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1bcc181aa254e91bfc333c966e4637d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97a9b32570d553161be04d13954e92a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00566b498fa4a541e154ffcf2c19d0fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b462c21e9d780337650cd97614d8327d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/423cd617e81adcbab86786cbe3cb6ade.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/6/54101104-b394-4628-8192-03563c15682c.png?resizew=156)
(1)求证:MN
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3fb82553d568ea8aae9d0dd89ae1ca2.png)
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【推荐3】如图,四棱锥
中,
为等边三角形,
平面
,
且
,
为
中点.
(1)求证:
平面
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5164a3cc47e266446d49127e2ef10c37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97f30533da2e1d2a958dc906c37eba9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9e22143a3f0cb2de51f382836cc274e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4a4f4bab704a302bfad5b025a44fd59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/28/fa4bc99f-8903-47d0-89c2-041400cad0cc.png?resizew=129)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97a9b32570d553161be04d13954e92a1.png)
您最近一年使用:0次
解答题-证明题
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适中
(0.65)
名校
解题方法
【推荐1】如图,二面角
的大小为
,四边形
是边长为
的正方形,
,
为
上的点,且
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/18/838d75b1-7f38-40a8-950f-b1c44f7d57c6.png?resizew=132)
(1)求证:
;
(2)求二面角
的大小;
(3)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d87b527147cb8dbb475bcefc0da2e6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d49f8a63ddbca52039fa9ab44cda6b29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c6c150511eead72eb15fc7284c6c363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fa3c61d6c19e187b4b824b6f5610cdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/18/838d75b1-7f38-40a8-950f-b1c44f7d57c6.png?resizew=132)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a48e31deb78dadacc7e128ef3eb2a054.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/001a1ffb477e4fde288a68618803b0e3.png)
(3)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
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【推荐2】如图1,在矩形
中,已知
,E为
的中点.将
沿
向上翻折,进而得到多面体
(如图2).
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/692ccba3-4c3b-4a9c-b6b7-f9d5defc972b.png?resizew=384)
(1)求证:
;
(2)在翻折过程中,求二面角
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff7d7574444029298002a42759a6426a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2db2b1c641b93caae9b7a82441e4ba70.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/692ccba3-4c3b-4a9c-b6b7-f9d5defc972b.png?resizew=384)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2181c78134c310f746eab44b9124e63b.png)
(2)在翻折过程中,求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f89e41e82409d264fac6d39300d4ea5.png)
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