如图,在正方体
中,
分别为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/4/0e5377cd-06ee-4056-b69f-06ce46042d85.png?resizew=151)
(1)证明:
平面
.
(2)若
,求四棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9a3c176cd586a25166fac58af2e43ea.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/4/0e5377cd-06ee-4056-b69f-06ce46042d85.png?resizew=151)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a5f445af1ae136773cb338920552ff2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/679748eab882a6be0fefd2cc300349a4.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f067183ddb143d5a2473ea7ab90ad7ae.png)
更新时间:2022-07-02 09:26:36
|
相似题推荐
解答题-问答题
|
较易
(0.85)
解题方法
【推荐1】如图(1),等腰梯形ABCD中,AD∥BC,AB=AD,∠ABC=60°,E是BC的中点,如图(2),将△ABE沿AE折起,使二面角B—AE—C成直二面角,连接BC,BD,F是CD的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/19/6a51342e-89ea-4f79-994e-314f1c75e03c.png?resizew=350)
(1)判断BC上是否存在一点P使得
平面
?如果存在请说明理由;
(2)若AD=2,求四棱锥B-AECD的体积.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/19/6a51342e-89ea-4f79-994e-314f1c75e03c.png?resizew=350)
(1)判断BC上是否存在一点P使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ee72dbf16db9bb8b5b51576a0619c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abd284f76d9f5769bc189508ce2572b.png)
(2)若AD=2,求四棱锥B-AECD的体积.
您最近一年使用:0次
解答题-问答题
|
较易
(0.85)
解题方法
【推荐2】如图,在正三棱锥
中,
,
.求
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60b4c1ae9c57d51e27bbdb001122d3bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b78b7332d36682ab26245459ee57d66e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/2/e855f61e-2248-45ff-b90e-6f82d84407da.png?resizew=172)
您最近一年使用:0次
解答题-问答题
|
较易
(0.85)
解题方法
【推荐1】如图,在四棱锥
中,四边形
是正方形,
平面
是
的中点,
是
与
的交点.
(1)证明:
平面
;
(2)求三棱锥
的体积.
![](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/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7ee9fad684dea61afcc941828c89356.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/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/19/c3d3fb50-9ec0-4e80-9565-da9946a609b0.png?resizew=169)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90deda6e128fade762bdb3b74bedf511.png)
您最近一年使用:0次
解答题-问答题
|
较易
(0.85)
解题方法
【推荐2】在棱长为
的正方体
中,
、
分别为
、
的中点,在
上是否存在一点
,使得
平面
,若存在求出
的长;若不存在说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.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/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78870dc2f09416598a67ff7c61023a54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a8035fc825a001d7d9a3dacd8271662.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
您最近一年使用:0次