四棱锥
底面是平行四边形,面
面
,
,
,
分别为
的中点.
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/386e51b9c432489696222f996417e04f.png)
(1)求证:![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/40f7b12f064e4b9db653d4dc72e748c7.png)
(2)求证:
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/a3464e05ed1e4d43bcdbb1312feef9b4.png)
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/e8224e8cabc84896a1c26d3214baf16d.png)
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/359d34a503c34fe0817b0a6211845529.png)
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/b5e05ac6640f4815bb224f5ba2bfde83.png)
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/00b060eaa4044766b3bea5ff368c77d2.png)
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/83c48dfc59a143bdb9c97b9d9c7dd988.png)
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/76d15388900f4000ae8672c660a9920d.png)
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/386e51b9c432489696222f996417e04f.png)
(1)求证:
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/40f7b12f064e4b9db653d4dc72e748c7.png)
(2)求证:
![](https://img.xkw.com/dksih/QBM/2015/12/1/1572333245972480/1572333252067328/STEM/16d7c48eb29b4009ae95831b9af529de.png)
更新时间:2016-12-03 21:03:06
|
相似题推荐
解答题-证明题
|
较易
(0.85)
【推荐1】
为等腰直角三角形,
,
,
、
分别是边
和
的中点,现将
沿
折起,使面![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/7c0a3b96b2704a378424003cda47dac5.png)
面
,
、
分别是边![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/9073703c7f8b4e7987d47774e2d71649.png)
和
的中点,平面
与
、
分别交于
、
两点.
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/537ac35fcb364ef4a7945ae57a82740f.png)
(Ⅰ)求证:![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/22761db4c74a462ea2b9ac8d7187f439.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/b850280235184247aba1a866facdbf6c.png)
;
(Ⅱ)求二面角
的余弦值;
(Ⅲ)求
的长.
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/b4bf254e014e43f295613df576170bc3.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/16015fc0d5ef4d52830219ce5aa2e55b.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/ed4cd6243c204cfca6b5d85306cfc129.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/6c76f5f6cbed4ea3ac9fa0d4e94bee88.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/584216596a3442b38dd04f1d109ae3e0.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/df5d2181513b4cfe9da005784ef6fb18.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/b2e69dfbe1ec47feb68aa3b93732102d.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/cc320511a05b43c6be999f9b151b509a.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/2f9903e0949d4c2897d10f885fae1497.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/7c0a3b96b2704a378424003cda47dac5.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/7e1c14b8d3dc4feeb62318a3bffc7b76.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/a9903f5e9f424a02b90dea213222aa6c.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/be3bf612969b4eec9cf0851c418fd09f.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/4a8eef49b2cf418c8bf4fe7bbc0c85b6.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/9073703c7f8b4e7987d47774e2d71649.png)
和
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/6415c7377faf479283d02ee980a254cb.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/a2e5c056e8264f8d8a33bdf39ddae40e.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/0bc260db9552485389e66dc55a5bdf52.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/3dc3e18cdb074fd1a21e9be06540bf6c.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/8b0db28dba0d4655a6ee066ff0a94faa.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/a2d3f97aa904438ab15eb93ee47c832b.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/537ac35fcb364ef4a7945ae57a82740f.png)
(Ⅰ)求证:
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/22761db4c74a462ea2b9ac8d7187f439.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/b850280235184247aba1a866facdbf6c.png)
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/ec7e687c076e4cadab8ca1e41d50d6e2.png)
(Ⅱ)求二面角
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/1f30f7eae31c48f58550ada1adb8fbeb.png)
(Ⅲ)求
![](https://img.xkw.com/dksih/QBM/2015/4/29/1572086904897536/1572086911066112/STEM/c575477ce3d141beb836538e68809593.png)
您最近一年使用:0次
解答题-证明题
|
较易
(0.85)
【推荐2】如图,在正四面体A-BCD中,点E,F分别是AB,BC的中点,点G,H分别在CD,AD上,且
,
.
![](https://img.xkw.com/dksih/QBM/2022/7/27/3031796311244800/3032367864479744/STEM/effe93b0719647d787accaede8883d16.png?resizew=158)
求证:直线EH,FG必相交于一点,且这个交点在直线BD上;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5da23247bd4f8bec01f73645dfd03c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21b488b36e825a6839852803ef6306d8.png)
![](https://img.xkw.com/dksih/QBM/2022/7/27/3031796311244800/3032367864479744/STEM/effe93b0719647d787accaede8883d16.png?resizew=158)
求证:直线EH,FG必相交于一点,且这个交点在直线BD上;
您最近一年使用:0次
解答题-问答题
|
较易
(0.85)
【推荐1】如图,在四棱锥
中,底面
为直角梯形,
,
底面
,
,
,
为
的中点,
为棱
的中点.
![](https://img.xkw.com/dksih/QBM/2017/2/10/1625065709297664/1625065709854720/STEM/a0cd6ad005d24527bedf8d1256842be7.png)
(I)证明:
平面
;
(II)已知
,求
点到平面
的距离.
![](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/0facf189b2a3153beb7b9e077d3b1146.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90ff6d7dd48b57f03d82d2c522ee9b94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e839ac941e8bf536ff35a12e56c7a400.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.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/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/2017/2/10/1625065709297664/1625065709854720/STEM/a0cd6ad005d24527bedf8d1256842be7.png)
(I)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/083b08552886374380117e5146525855.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c233190f9339e777fe26c7b690541baf.png)
(II)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e159921cdcf0e3bb64ddc32015e1a361.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c233190f9339e777fe26c7b690541baf.png)
您最近一年使用:0次
解答题-证明题
|
较易
(0.85)
【推荐2】如图所示的几何体中,四边形CDEF为正方形,四边形ABCD为等腰梯形,AB∥CD,AC=,AB=2BC=2,AC⊥FB.
![](https://img.xkw.com/dksih/QBM/2016/10/9/1573059137609728/1573059143180288/STEM/0036c8a0af6f4dea93e0987fe3c92560.png)
(1)求证:
;
(2)求点
到平面
的距离.
![](https://img.xkw.com/dksih/QBM/2016/10/9/1573059137609728/1573059143180288/STEM/0036c8a0af6f4dea93e0987fe3c92560.png)
(1)求证:
![](https://img.xkw.com/dksih/QBM/2016/10/9/1573059137609728/1573059143180288/STEM/486e23252fa644038cc30b891ead984e.png)
(2)求点
![](https://img.xkw.com/dksih/QBM/2016/10/9/1573059137609728/1573059143180288/STEM/5b5041d974f0427f8e07ec74e517d50d.png)
![](https://img.xkw.com/dksih/QBM/2016/10/9/1573059137609728/1573059143180288/STEM/a69c92bf07ca4d7b88232dd1f43f80a3.png)
您最近一年使用:0次