1 . 已知数列
满足
,且
.
(1)求证:
是等差数列;
(2)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/950c6303c2ec03e48137be8addf9245c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7b78e4a03d4595f14be42054b61dfc6.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe2d091607ee8419029109a54cb45ab.png)
您最近一年使用:0次
解题方法
2 . 如图,在三棱锥
中,
,D、E分别是AB、AC的中点,且
平面ABC.
![](https://img.xkw.com/dksih/QBM/2020/3/12/2418141298819072/2432991658786816/STEM/3eec0a29c1374b0bb538621cd7a01891.png?resizew=284)
(1)求证:
平面PDE;
(2)求证:
平面PDE.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db807b09cc550f476b3f8fa0c6a14425.png)
![](https://img.xkw.com/dksih/QBM/2020/3/12/2418141298819072/2432991658786816/STEM/3eec0a29c1374b0bb538621cd7a01891.png?resizew=284)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/963a91995abd4927d75406d16e10a81f.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
您最近一年使用:0次
2020-04-02更新
|
720次组卷
|
3卷引用:重庆市2017年普通高中学业水平考试数学试题