如图,在直四棱柱
中,
、
分别是
、
的中点,
与
交于点
.
![](https://img.xkw.com/dksih/QBM/2016/2/15/1572473081249792/1572473087172608/STEM/3cbee84975ea43b1a26bdd27e265f4a9.png?resizew=264)
(1)求证:
、
、
、
四点共面;
(2)若底面
是菱形,且
,求证:
平面
.
![](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/a0ed1ec316bc54c37c4286c208f55667.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/0f1f229274a6e17977cc047814212589.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cfbc0b5a8fbde804bd8425a4b76d207.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://img.xkw.com/dksih/QBM/2016/2/15/1572473081249792/1572473087172608/STEM/3cbee84975ea43b1a26bdd27e265f4a9.png?resizew=264)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
(2)若底面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bd63d2c47dc701287f143be83799749.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02cbddc9b1f36e2cabd9a6c830d14736.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/198a3a349dea507e9fc99d5f5ed0642c.png)
更新时间:2016-12-04 01:47:35
|
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】如图,在三棱柱
中,
平面
,
,
,且
,
,
,
分别为棱
,
,
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/2/7d81a2bc-5e54-4de8-862f-520416c3ceb5.png?resizew=147)
(I)证明:直线
与
共面;
(Ⅱ)证明:平面
平面
;并试写出
到平面
的距离(不必写出计算过程).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a8bfe2553e852df73185d017c0a62fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/520828c9d9e777117f6d432babee0816.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/615fc8790237a1b09af51d6bcad6b595.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/6795cae2df43a722e1355e9562d93c09.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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/2/7d81a2bc-5e54-4de8-862f-520416c3ceb5.png?resizew=147)
(I)证明:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f35f348ed8a1690d3ed02aa64459ca50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f1158eaa2e338f564eb18de5bef1d25.png)
(Ⅱ)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97a42a2d800a18fe28ece3147ae5e623.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c52091eb745de866044477641a7c55f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/458d492ab8896be57a54ec905d8e2f4f.png)
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解答题-证明题
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适中
(0.65)
【推荐2】过异面直线中一条直线上的各点,引另一条直线的平行线.求证:这些直线必在同一平面内.
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解答题-证明题
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适中
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名校
【推荐1】如图,在四棱锥
中,
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e800b64fbd8e88227aa9fae21b17e1a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
为侧棱
上一点,平面
与侧棱
交于点
,且
与底面
所成的角为
.
为线段
的中点;
(2)求平面
与平面
的夹角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/218054144a13435580cd132b9459546c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
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解答题-证明题
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适中
(0.65)
【推荐2】如图,在多面体
中,
四点共面,
平面
,
为
的中点.
平面
;
(2)求平面
与平面
所成二面角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9142a8490de14a87eda628ffa7e28982.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/500df0e782bb081e608f4bc1d576afcf.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10fc7991ea17d54ff5f4445ac5699463.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
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解答题-证明题
|
适中
(0.65)
名校
【推荐3】如图,在几何体
中,底面
为以AC为斜边的等腰直角三角形.已知平面
平面
,平面
平面
,
平面
,
,
,
为垂足,
,
为垂足.
平面
;
(2)若
,设
为棱
的中点,求当几何体
的体积取最大值时,
与
所成角的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9142a8490de14a87eda628ffa7e28982.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
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(2)若
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