判断下列命题是否正确,并说明理由:
(1)若
,
,则
;
(2)若
,
,则
.
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11c56d479e3620d764eccab05fe0a1e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8a4352562ae8aa968014fd0d931b677.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0477d21c9b3704ca34e2a607429ea602.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e076b91a9178217532e11c496400e8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8a4352562ae8aa968014fd0d931b677.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0477d21c9b3704ca34e2a607429ea602.png)
21-22高一·湖南·课后作业 查看更多[2]
更新时间:2022-02-22 19:26:55
|
【知识点】 判断线面平行
相似题推荐
解答题-证明题
|
容易
(0.94)
解题方法
【推荐1】如图,在正方体
中,
与
交于点
,求证:
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/15/208b1629-1617-47fb-a477-2b7a25f41e43.png?resizew=223)
(1)直线
平面
;
(2)直线
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f1f229274a6e17977cc047814212589.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cfbc0b5a8fbde804bd8425a4b76d207.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f919bd3dde10dbbc076f7ec5149699.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/15/208b1629-1617-47fb-a477-2b7a25f41e43.png?resizew=223)
(1)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4cc24037ff3b29f2cb81291734869d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da7977ab975efa6411cc17de39be70d9.png)
(2)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78dc7ff50bce3962f5607b4da34f5532.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da7977ab975efa6411cc17de39be70d9.png)
您最近一年使用:0次
解答题-证明题
|
容易
(0.94)
解题方法
【推荐2】如图,已知四棱锥
的
底面为直角梯形,
,
,
,
且
,M是
的中点.
![](https://img.xkw.com/dksih/QBM/2010/11/18/1569906658918400/1569906664251392/STEM/ad2436e417b2497b9a12428a934a5c0e.png?resizew=209)
(1) 证明:
;
(2) 求异面直线
所成的角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
底面为直角梯形,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ee8ef58be8708144272538ee427fb92c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9823d3daa8b68d02aaf19405c5788569.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ecc618a61b606792fb1913410f0d181.png)
且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bda1a7eeb84ee2f5f723c78de0867aa1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://img.xkw.com/dksih/QBM/2010/11/18/1569906658918400/1569906664251392/STEM/ad2436e417b2497b9a12428a934a5c0e.png?resizew=209)
(1) 证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/253a38bcce8543b07d506878f3431ceb.png)
(2) 求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da2e5e2ad957a19754e049cb8a2c3de0.png)
您最近一年使用:0次