1 . 如图,已知
,
分别是正方形
边
、
的中点,
与
交于点
,
、
都垂直于平面
,且
,
,
是线段
上一动点.
![](https://img.xkw.com/dksih/QBM/2015/10/8/1572247535755264/1572247541628928/STEM/10ee63f2d5a241b5a5c86931a8515522.png)
(Ⅰ)求证:平面
平面
;
(Ⅱ)若
平面
,试求
的值;
(Ⅲ)当
是
中点时,求二面角
的余弦值.
![](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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dafebaaf13781120dc57c277d0267c0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9a4950a6e4202efd609507964af238b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18091448701460b53e076331e7c575cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://img.xkw.com/dksih/QBM/2015/10/8/1572247535755264/1572247541628928/STEM/10ee63f2d5a241b5a5c86931a8515522.png)
(Ⅰ)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba9008f244e609ad267e10b8861c8254.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94cc30d46b4538a4c86064df7460356.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bb178784aa857d4d4683e650273f054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed4cba9d2412e4a28f8740bddd5738d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ad337a2ee42c1d43458859014c54b92.png)
(Ⅲ)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fa5cd4da0137515627593735100978e.png)
您最近一年使用:0次
解题方法
2 . 如图,在正四面体
中,
分别是棱
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/1/57f0cb5f-ca83-4275-9415-9658094a7031.png?resizew=199)
(1)求证:四边形
是平行四边形;
(2)求证:
平面
;
(3)求证:
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e5db1d2fd912f77923e4c120a7dc19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42c2d86d8daea5e652d99fe1c6bc3f9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5e70a154a566e178a94bdad0fdaef2e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/1/57f0cb5f-ca83-4275-9415-9658094a7031.png?resizew=199)
(1)求证:四边形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a829577bb0863d3f39db38ca4c179a56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/611f100dcfa7803db6eb233e2e7f2dab.png)
(3)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963382b353991f4698111a46483d4e0.png)
您最近一年使用:0次
14-15高二上·广东汕头·期末
名校
3 . 如图,
为圆
的直径,点
.
在圆
上,且
,矩形
所在的平面和圆
所在的平面互相垂直,且
,
.
![](https://img.xkw.com/dksih/QBM/2014/3/28/1571585931689984/1571585936973824/STEM/e70bdd0a74af4b1dad1f9bf296ec83af.png)
(1)设
的中点为
,求证:
平面
;
(2)求四棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.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/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c91baecb97fadd4f8ab49e6effcbc04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a951292add4574c1debd16800674e1e.png)
![](https://img.xkw.com/dksih/QBM/2014/3/28/1571585931689984/1571585936973824/STEM/e70bdd0a74af4b1dad1f9bf296ec83af.png)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/280247d7df395bb9ea78c51e67b458d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c93a34cbd4c0dc198b74524c0e05a10.png)
(2)求四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37e7b3a2c6ad3c82b8091e721c58e4e2.png)
您最近一年使用:0次
4 . 已知:如图,等腰直角三角形
的直角边
,沿其中位线
将平面
折起,使平面
⊥平面
,得到四棱锥
,设
、
、
、
的中点分别为
、
、
、
.
![](https://img.xkw.com/dksih/QBM/2014/10/14/1571877245075456/1571877251039232/STEM/3e2168d2f99e4b2095039bd51bd77375.png)
![](https://img.xkw.com/dksih/QBM/2014/10/14/1571877245075456/1571877251039232/STEM/75a95f0463b841f1b96efcc5223e3665.png)
![](https://img.xkw.com/dksih/QBM/2014/10/14/1571877245075456/1571877251039232/STEM/a4452ef92c0c41ab9cb8ee8473b974bb.png)
(1)求证:
、
、
、
四点共面;
(2)求证:平面
平面
;
(3)求异面直线
与
所成的角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/209acf15985d1ea1ad86fc4a37e38c0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/648d3522c3b735dc050676fa95beb3c8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.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/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://img.xkw.com/dksih/QBM/2014/10/14/1571877245075456/1571877251039232/STEM/3e2168d2f99e4b2095039bd51bd77375.png)
![](https://img.xkw.com/dksih/QBM/2014/10/14/1571877245075456/1571877251039232/STEM/75a95f0463b841f1b96efcc5223e3665.png)
![](https://img.xkw.com/dksih/QBM/2014/10/14/1571877245075456/1571877251039232/STEM/a4452ef92c0c41ab9cb8ee8473b974bb.png)
(1)求证:
![](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/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfa640b17a9d7bfb7242f27fe0a4012a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
(3)求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2dca049735b45fb9b2533c68605eddc.png)
您最近一年使用:0次
5 . 下列命题中假命题是
A.垂直于同一条直线的两条直线相互垂直 |
B.若一条直线平行于两个相交平面,则这条直线与这两个平面的交线平行 |
C.若一个平面经过另一个平面的垂线,那么这两个平面相互垂直 |
D.若一个平面内的两条相交直线与另一个平面内的相交直线分别平行,那么这两个平面相互平行 |
您最近一年使用:0次