《九章算术》中,将四个面都是直角三角形的四面体称为“鳖臑”,如图所示,四面体
中,
平面
,
,
是棱
的中点.
(1)判断四面体
是否为鳖臑,并说明理由;
(2)若四面体
是鳖臑,且
,求直线
与平面
所成的角的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a351136b18bc7d3bd5122332772ab23b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b10134e7a46e6f6f7cb9d5e2371727d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/3/4c92d23c-f6d7-4450-b4ff-a587e7286502.png?resizew=146)
(1)判断四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8922620e649f55d79118cbabf947a8fa.png)
(2)若四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a351136b18bc7d3bd5122332772ab23b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de2479cd9055e57e504d64ea7d97e71e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
更新时间:2023-11-11 11:07:24
|
相似题推荐
解答题-问答题
|
较易
(0.85)
解题方法
【推荐1】如图,在四棱锥
中,底面
是边长为2的正方形,侧棱![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
底面
,
,
是
的中点,作
交PB于点
.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/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43d4c42112e0a22f240ce2ae432e5b4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a4a6a1e70241d600bc6c104313eac61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8ee3afb7e2c8943673449a1b136faf0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/2/fb140ba9-c070-4214-b16d-57f091beb4c4.png?resizew=168)
您最近一年使用:0次
解答题-证明题
|
较易
(0.85)
解题方法
【推荐2】如图,在正方体
中,
,
分别为
,
的中点.
平面
;
(2)求证:
;
(3)求证:
,
,
,
四点共面.
![](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/394c5d2f55221975503be8aa18022480.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5fbafedc202bd0d86c4dfdece9f8f4fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81cd138921c73b4cd561adf3c5e1003b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc9e71a5b01119a28986d1b83fd39d87.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a778e0635e340c5dd443d8ba15f8470.png)
(3)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.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1】已知
在平面
内,
是平面
的一条斜线,若
,
,
,求
与平面
所成的角.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d22df2977de56cc69be0c1e847653d7a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c66aa9636ddecb69feb1dc17dc515a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c9f290721719fd610149b309467560e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1637bdd312c725548074cb47bef3e168.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.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,已知AB丄平面BCD,M、N分别是AC、AD的中点,BC 丄 CD.
![](https://img.xkw.com/dksih/QBM/2017/10/19/1798750472773632/1800617931898880/STEM/5dff8f1dfeef4fc0a17eec1107028587.png?resizew=211)
![](https://img.xkw.com/dksih/QBM/2017/10/19/1798750472773632/1800617931898880/STEM/5dff8f1dfeef4fc0a17eec1107028587.png?resizew=211)
(1)求证:MN//平面BCD;
(2)若AB=1,BC=,求直线AC与平面BCD所成的角.
您最近一年使用:0次
解答题-问答题
|
较易
(0.85)
【推荐3】如图,在四棱锥P-ABCD中,
底面ABCD,
,
,
,
,E是PC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/16/2bda7570-8541-47b1-beef-792cbd959ec8.png?resizew=154)
(1)求PB和平面PAD所成的角的大小;
(2)证明
平面PCD;
(3)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3bf10d92f20501e19d25f6f4159aab89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ace900749d0861aa51fcc6d72c51f82c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/16/2bda7570-8541-47b1-beef-792cbd959ec8.png?resizew=154)
(1)求PB和平面PAD所成的角的大小;
(2)证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4c3f9dd5d0343597a7f58a1989b537.png)
(3)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e867e5c7ef4da37d8985ce82022060e.png)
您最近一年使用:0次
解答题-证明题
|
较易
(0.85)
名校
【推荐1】在三棱锥
中,
,
,
.
![](https://img.xkw.com/dksih/QBM/2021/2/21/2662695557177344/2663649491869696/STEM/dc6d0cd82db442a5bcc08880d86ecc7e.png?resizew=219)
(1)求证:
;
(2)若
为
上一点,且
,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37ac37630bf01a67dab22f61ce6e726a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e4b3e69d88c077cbe7cbd0f1223c65c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb5b12692517a39c320f99a479eb055.png)
![](https://img.xkw.com/dksih/QBM/2021/2/21/2662695557177344/2663649491869696/STEM/dc6d0cd82db442a5bcc08880d86ecc7e.png?resizew=219)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70734a8e672376bb0bd1522e229f86a2.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d15a7f431aa107bd61b87f454e1f541.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
您最近一年使用:0次
解答题-证明题
|
较易
(0.85)
解题方法
【推荐2】如图,在四棱锥中
中,
,
,
,
,
是正三角形.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/22/fefe71de-e744-4ee3-9525-7dd09fcaaee8.png?resizew=142)
(1)求证:
;
(2)求
与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdb2dd10731b99c0f4f89ee957f8a239.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58c9d5c0b9d7b7cf3e14f56bc3b4ac2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6914d401b0e7099dbea8ebdd5052ee7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6e2903ff33266528a7902ad51cf8d75.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/22/fefe71de-e744-4ee3-9525-7dd09fcaaee8.png?resizew=142)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0530f462e5ec1e58c46e1f7644d0cc21.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
您最近一年使用:0次