如图,棱长为
的正方体
中,
是棱
上靠近
的三等分点.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/13/fa142223-f04a-443a-919f-815aa6cd9560.png?resizew=159)
(1)求证:
与平面
不垂直;
(2)在线段
上是否存在一点
使得平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68329e13570eccb6e87f6545d65dfd2c.png)
平面
?若存在,请计算
的值;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](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/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/13/fa142223-f04a-443a-919f-815aa6cd9560.png?resizew=159)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68329e13570eccb6e87f6545d65dfd2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4f94ad6cf5f11c1fedb78462429c774.png)
更新时间:2024-03-13 08:50:00
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图所示,已知正方体
的棱长为
分别是
的中点,
是
上一点,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/7/d13caa2e-602a-4bd1-81d1-18b5bc3d932c.png?resizew=174)
(1)证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
平面
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89952953873ddf693370dedd910d86be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79c4bf3d636b63efd9cbc1b0de58f8be.png)
![](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/520e213ecdc97d202c37ca8356a979fc.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/4/7/d13caa2e-602a-4bd1-81d1-18b5bc3d932c.png?resizew=174)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c08b9a48b3f89132f323efcdb014430.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/becf2941e15d668d93ea6ed980afd0ba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c08b9a48b3f89132f323efcdb014430.png)
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解答题-证明题
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(0.65)
名校
【推荐2】在四棱锥P-ABCD中,侧面
底面ABCD,
,底面ABCD是直角梯形,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5cbd09570da60e122ab44e7091f8e56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/849db8bf6e74601bf55b5675004522ff.png)
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/faeb7685-9e4a-4a82-a960-126e6df58e15.png?resizew=261)
(1)求证:
平面PBD:
(2)设E为侧棱PC上异于端点的一点,
,试确定
的值,使得二面角E-BD-P的余弦值为
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/342d452a7b850cd3a15b23619ad39bd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37002ada5d194d4d062fa3285d7d9824.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be609874d9f797afd8364408a810c934.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5cbd09570da60e122ab44e7091f8e56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/849db8bf6e74601bf55b5675004522ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/833cfda415649b832cc136caed392753.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/1/faeb7685-9e4a-4a82-a960-126e6df58e15.png?resizew=261)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
(2)设E为侧棱PC上异于端点的一点,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59d3b671f966d7a45c7116e151f41deb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1174142f3bba761585b6bc2653009b36.png)
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解题方法
【推荐1】如图,在四棱柱
中,四边形
是平行四边形,
,
,
,
,
为
的中点,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/25/65110a90-a035-447d-a6b6-2bc1b1cbee32.png?resizew=169)
(1)过点
作四棱柱的截面使其与面
垂直,并予以证明;
(2)若平面
与平面
的夹角的余弦值为
,求三棱锥
的体积.
![](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/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65a3e478bb87d094e3a0af30dd10ae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05740f0c6071846227dc0ec177ad15e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c078a10649b3a953631690021aa59879.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/59fc4baf66de980a95f267051e6b190d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/25/65110a90-a035-447d-a6b6-2bc1b1cbee32.png?resizew=169)
(1)过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bf9628142422a4884bd59538da6d312.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/924d32b574fe69e43724304cf39513e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a35ac94f0ea5d79ae4530f5a3116f670.png)
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解答题-证明题
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适中
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名校
【推荐2】如图,在四棱锥
中,底面
是矩形,侧面
底面
为线段
的中点,过
三点的平面与线段
交于点
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/18/3457b1d5-105d-4dbb-be6b-7a35c7e95864.png?resizew=188)
(1)证明:
;
(2)若四棱锥
的体积为
,则在线段
上是否存在点
,使得二面角
的正弦值为
?若存在,求
的值;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/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23d11e19c84255eb0431415c2dec553d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d14af8de7575341e02ee92cd0e33312b.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/f8bb7451bce637c6171cf344eb9de43e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/18/3457b1d5-105d-4dbb-be6b-7a35c7e95864.png?resizew=188)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab1a1fd2fc33e89f357cef772ff6cd0e.png)
(2)若四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a391005600bdd69c96750589f9adb048.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a155d285d8d487adf9fac93a48bb0700.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dee14db57f0c762aad845cf5b4a243c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6729fb0c5e5e9549035590144b73144.png)
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【推荐3】如图所示的几何体中,底面ABCD为直角梯形,
,
,四边形PDCE为矩形,平面
平面ABCD,F为PA的中点,N为PC与DE的交点,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/1/2424014c-8d14-426c-8a28-9caffd3b5f29.png?resizew=202)
(1)求证:
平面
;
(2)若G是线段CD上一点,平面PBC与平面EFG所成角的余弦值为
,求DG的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6379891c7150af4188b5ab746d703bae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbe7a201432af0a2f9d21c6803906f5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0046177466c78f08d45449dc5639bf38.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/1/2424014c-8d14-426c-8a28-9caffd3b5f29.png?resizew=202)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d53d5c96de34fcf95794e51c2761b671.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)若G是线段CD上一点,平面PBC与平面EFG所成角的余弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64f1145c162038df3c7184d9201c628e.png)
您最近一年使用:0次