已知多面体
中,
为矩形,
平面
,
,且
,
,
,点
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/af8763e6-ac5f-4a12-bc36-6b9576fa41f9.png?resizew=159)
(1)求证:
平面
;
(2)求二面角
的平面角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2fc1129846f37afdafd751627c450d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed04b01505bbd8a4ac0bc12e46f23bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ccbe7b7e304f13142684268baa477d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7be724cff092529ea0759a9bee9555a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68b40d0d2f3cdd8981bb792ad87efb42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5bbe1abbe2d935aa1a2fd91bd5b5019.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/af8763e6-ac5f-4a12-bc36-6b9576fa41f9.png?resizew=159)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e2fef2c0e49ecae8688ca60802310e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9efe66d99f813c6b1387392186822bb.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19fa7ff056747ebdc342dc2ddf1b4b16.png)
更新时间:2020-02-15 20:35:03
|
相似题推荐
解答题-问答题
|
较易
(0.85)
解题方法
【推荐1】如图,在直三棱柱
中,
,且
,点M、N分别为棱
和BC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/29/ff2b56c3-6922-43ad-acce-5148c768c1ae.png?resizew=135)
(1)证明:证明
//平面
;
(2)求点M到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f90e17995e2f71e297d94ae51c7e5b1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/29/ff2b56c3-6922-43ad-acce-5148c768c1ae.png?resizew=135)
(1)证明:证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91a114d968325e799e60de7ae82d1936.png)
(2)求点M到平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91a114d968325e799e60de7ae82d1936.png)
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【推荐2】如图,直三棱柱
中,
、
分别是
、
的中点,
,证明:
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.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/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b22fed75dd7ef9141977dc9f6bf6d8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cd597851c0db4e4de4769e10e09383b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74bca84ad86c648d3bb20c8909c8da3f.png)
![](https://img.xkw.com/dksih/QBM/2022/2/25/2924039425302528/2934841274155008/STEM/e84d1b894ae545d5b81524351e2bcdd0.png?resizew=163)
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【推荐3】如图,在正方体
中,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/7/726c5a24-1dcf-4d63-8f67-d0e661eff4bf.png?resizew=180)
(1)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fe734023d4e70010a6b2cc3267cb86e.png)
平面
;
(2)设
是棱
上一点,当二面角
的余弦值为
时,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22adbc0da438220f9cace11b629d799b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/7/726c5a24-1dcf-4d63-8f67-d0e661eff4bf.png?resizew=180)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fe734023d4e70010a6b2cc3267cb86e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a9bfa68259d7a331be323b2038d628a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4cb797a03b0d96fa146543101f993c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e08e91d2fa9519a5f48d488176700499.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd6fd3cefafb2088a8b68fde9fd0eee7.png)
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解题方法
【推荐1】如图,几何体AMDCNB是由两个完全相同的四棱锥构成的几何体,这两个四棱锥的底面ABCD为正方形,
,平面
平面ABCD.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/4672e2fb-463e-42f9-a627-babbec5f9a3b.png?resizew=129)
(1)证明:平面
平面MDC.
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1cb00f33c913f17892b24ed2edb99f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e05d8681a679bd31922e62480f69d55.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/4672e2fb-463e-42f9-a627-babbec5f9a3b.png?resizew=129)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72aaf3dd6430012945b647bdb51042c.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8bd7c7eb6140f3acc14ff33b110d7d9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/124d082ef5b7abb60b1035776ed2c1b6.png)
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【推荐2】在四棱锥P-ABCD中,平面ABCD⊥平面PCD,底面ABCD为梯形,AB∥CD,AD⊥DC,且AB=1,AD=DC=DP=2,∠PDC=120°.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/6/9fcaafbe-fb87-43d3-add9-83b42f7e861d.png?resizew=161)
(1)求证:AD⊥PC;
(2)求二面角P-AB-C的余弦值;
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/6/9fcaafbe-fb87-43d3-add9-83b42f7e861d.png?resizew=161)
(1)求证:AD⊥PC;
(2)求二面角P-AB-C的余弦值;
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