如图,四边形ABCD是矩形,AB=2BC,E为CD中点,以BE为折痕将
折起,使C到
的位置,且平面
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1d70676406f26d339465fe3473c0c05.png)
(1)求证:
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b1a2dbe2665ec6a0fadff8e19da12f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4c8a9c4957431681ddfc77895a88508.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af4db79ed8c305bed8a99642a0405446.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1d70676406f26d339465fe3473c0c05.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1077fc902532f6c4feff74b0b4a3238c.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6c08c7a3f9792dfcc801a6722cbf141.png)
![](https://img.xkw.com/dksih/QBM/2018/9/6/2026555454922752/2042298815995904/STEM/c4f36419434446abba0b07d09d8d98c9.png?resizew=221)
更新时间:2018-09-28 20:50:29
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在三棱柱
中,已知
侧面
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fa19cfedf20905f6700185d57fa8041.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/bf842ecf-9eaf-4400-887c-0d618b868615.png?resizew=162)
(1)求证:
平面
;
(2)若
是
的中点,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d46133b56840b2a8c4f6776cdcaee267.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6fa19cfedf20905f6700185d57fa8041.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/bf842ecf-9eaf-4400-887c-0d618b868615.png?resizew=162)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06ad7c180d6d084ecb25f23cb6fe9b10.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02b20ef9d660baa101c0574c46e107e0.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,在三棱台
中,
平面
,
为
中点.,N为AB的中点,
//平面
;
(2)求平面
与平面
所成夹角的余弦值;
(3)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1ecf072589c0f901d92f6bda111d841.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7d13df842e0c8e5fdd73648470371bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/764509115979e9958101808383672ec0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a604466a9c8d10d557b3dfc43b547065.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d3d41297bee8eeaca0c44cb7e8301ca.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d3d41297bee8eeaca0c44cb7e8301ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
(3)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d3d41297bee8eeaca0c44cb7e8301ca.png)
您最近一年使用:0次
解答题-问答题
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适中
(0.65)
名校
【推荐3】如图,在四棱锥
中,底面
是菱形,
,
,
,
底面
,
,点
在棱
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/24/5f861a4f-d7cb-4a21-8a71-6b1bc5b4be21.png?resizew=216)
(1)证明:平面
平面
;
(2)求二面角
的余弦值.
(3)求四面体
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/05740f0c6071846227dc0ec177ad15e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a23f01af749100e1888bba06268843db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3e126c16032892966489053f44b9048.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae890f9e8b32aa53a54158f24f4a87bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cc72a44dad13532cb9ddcc64bd78105.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/24/5f861a4f-d7cb-4a21-8a71-6b1bc5b4be21.png?resizew=216)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f04c222223dae9ef27d4c132534d9848.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5102c216393e133fa25dba98cd78535.png)
(3)求四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f178906e90bafd73e0ef9f89814855d5.png)
您最近一年使用:0次
解答题-问答题
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适中
(0.65)
解题方法
【推荐1】如图,在直三棱柱
中,底面
是边长为
的等边三角形,且
,
为
的中点,
是棱
上一动点(不包括端点).
![](https://img.xkw.com/dksih/QBM/2022/1/10/2891473245134848/2895932147384320/STEM/a13a7e08-794b-4405-be32-ec4d640d34d6.png?resizew=165)
(1)若
为
的中点,证明:
平面
;
(2)若
,求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ca7d1107389675d32b56ec097464c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d97f616f0f32beed421129cbbb4db8d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://img.xkw.com/dksih/QBM/2022/1/10/2891473245134848/2895932147384320/STEM/a13a7e08-794b-4405-be32-ec4d640d34d6.png?resizew=165)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69bcb3226e013650b7d8827c31dd41d0.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c7e14e831eff03260470e3720617071.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abd284f76d9f5769bc189508ce2572b.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图,在三棱柱
中,
,平面
平面
.
![](https://img.xkw.com/dksih/QBM/2022/5/13/2978517077884928/2978759161257984/STEM/8d609219-9756-4bb4-b9fd-e22f9de510f6.png?resizew=270)
(1)求证:
﹔
(2)若M是线段
的中点,N是线段
上一点,且
//平面
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a0b110750f5d9734f232068a185b1e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0671b4776e142e17a79af5b3f0378ef7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://img.xkw.com/dksih/QBM/2022/5/13/2978517077884928/2978759161257984/STEM/8d609219-9756-4bb4-b9fd-e22f9de510f6.png?resizew=270)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a28c816a483692b63e228cee6e8ac57.png)
(2)若M是线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f1f229274a6e17977cc047814212589.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4e16782710d9ecd1113770ab633446c.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐3】如图,在四棱锥
中,四边形
为菱形,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/a73afc84-5403-4139-8f21-efe519f59fe5.png?resizew=206)
(1)证明:
;
(2)若
,求二面角
的正弦值.
![](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/f14f698605a196cf83ccba6a601d0e2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c583493109d50c9e4634c05e9042a9f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/a73afc84-5403-4139-8f21-efe519f59fe5.png?resizew=206)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ff29971ccc633d89832ffa9bd54afa3.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5a9a04de2ddcec2b2799ab5476f2c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e867e5c7ef4da37d8985ce82022060e.png)
您最近一年使用:0次