2020高三·全国·专题练习
1 . 如图所示,三棱柱
的底面是边长为2的正三角形,侧棱
底面
,点
,
分别是棱
,
上的点,点
是线段
上的动点,
.
![](https://img.xkw.com/dksih/QBM/2020/12/23/2620404804395008/2622793088540672/STEM/8cb82b42-86a9-4467-b95f-90c90534d627.png?resizew=183)
(1)当点
在何位置时,
平面
?
(2)若
平面
,判断
与
的位置关系,说明理由;并求
与
所成的角的余弦值.
![](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/7bef5239ddbb0972700ce01daf9ee7cf.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/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12857c14dd0482aae811748caede4420.png)
![](https://img.xkw.com/dksih/QBM/2020/12/23/2620404804395008/2622793088540672/STEM/8cb82b42-86a9-4467-b95f-90c90534d627.png?resizew=183)
(1)当点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f369bec2d5682bf6b8b317a08aff546.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/982d01f052709b72afeaf1015fc7acc8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
您最近一年使用:0次
2 . 如图,三棱柱
的所有棱长均为
,底面
侧面
,
为
的中点,
.
![](https://img.xkw.com/dksih/QBM/2019/1/14/2118643569844224/2119113067282432/STEM/5cce867b62314992832795a2b2928792.png?resizew=202)
(1)证明:
平面
.
(2)若
是棱
上一点,且满足
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ede6a60cad0e0b58e1549fda6e085719.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99bfa2ca4e398c8ab0f97f47add3754f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8d55f92fba01d16c84c9a6b48b64c14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c02691431ef4a3d2395100c1f1b83b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b094e639c2b31dc54b1b3e6456e77843.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07e3f1fa2915d61429ff48b78d6bed5c.png)
![](https://img.xkw.com/dksih/QBM/2019/1/14/2118643569844224/2119113067282432/STEM/5cce867b62314992832795a2b2928792.png?resizew=202)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fe2f20fc44f314a589b3a0be781045a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d96f31276bc67d1da3398e0cef9b41ae.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1a9c6a736e6eac98a676fa3232db5a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f524a06030e52ae3832449523d2bb361.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee0d7c4f11e7e4704be278b7c7c9f39.png)
您最近一年使用:0次
2017-11-06更新
|
946次组卷
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3卷引用:河南省洛阳市2019-2020学年高二上学期期末考试数学(理)试题