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1 . 函数的凹凸性的定义是由丹麦著名的数学家兼工程师Johan Jensen在1905年提出来的.其中对于凸函数的定义如下:设连续函数
的定义域为
(或开区间
或
,或
都可以),若对于区间
上任意两个数
,均有
成立,则称
为区间
上的凸函数.容易证明譬如
都是凸函数.Johan Jensen在1906年将上述不等式推广到了
个变量的情形,即著名的Jensen不等式:若函数
为其定义域上的凸函数,则对其定义域内任意
个数
,均有
成立,当且仅当
时等号成立.
(1)若函数
为
上的凸函数,求
的取值范围:
(2)在
中,求
的最小值;
(3)若连续函数
的定义域和值域都是
,且对于任意
均满足下述两个不等式:
,证明:函数
为
上的凸函数.(注:
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4776c85b79df196f606d3ebf3697fbc3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4562f3225c98cf5cb11b47d98c9cc9c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4b3dce3b2dd078fdd6b4cfd301927f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b0c0214295e38221c4e98d13a8b6b37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4776c85b79df196f606d3ebf3697fbc3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ce7ae90d808f05e86ea063238e4b2f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1bedaf3854b48806b82b3b804451cf8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4776c85b79df196f606d3ebf3697fbc3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb2d0d76b383beb0f422ed02a2b888b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c83590c4a7ea5636843dd4b60c67cb40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ae7a1a59fbb460ff17c32dc7e3bb4ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73223617c8855826298d435673787a94.png)
(1)若函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165c6db50a97f8ed52b759e57ba2644.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a43b2faa4f81f32d94612dce724e772b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(2)在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82822f0c261ac2193ef264fe68321833.png)
(3)若连续函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be1ce3f01e2b6364f9a9fdaf197d5e29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/870ebc2f7aabb028024894568d749934.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea9484fcea82180e9886a18d7a947b03.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/963c40a0a3722b8f432ee37eef7cb1a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa06f4df6281bd147ce5bd8332cfb66e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/870ebc2f7aabb028024894568d749934.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56b9605ab2765c9811e9432e38d905e.png)
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2 . 在
中,
,
,
为
边的中线,
为
的中点,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/645ce289c7cd2c004a200cfe5372d36b.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ece8b2caad657f29ad830d78abd54a66.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1af98f1fb74e141fe4652c337f27bc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/645ce289c7cd2c004a200cfe5372d36b.png)
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解题方法
3 . 已知
,
,则
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3dcbe8b4bcd32e5a64ebfd873f8cbb2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2302d1f4ff928b0104889eb112684161.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/850dba25bf0f5f13541bf9b6ec12b84d.png)
A.![]() | B.![]() | C.1 | D.![]() |
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解题方法
4 . 定义平面向量
在
上的投影为
.若平面向量
,
满足
,则
在
上的投影的取值范围是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/861799183cfb793379ed465d98e6d62d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c4e99dcf45b4894d01f2828c5292364.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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2024·全国·模拟预测
解题方法
5 . 如图,在直三棱柱
中,
为线段
的中点,
为线段
(包括端点)上一点,则
的面积的取值范围为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2317dfec35762832f026ec62b20a690.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c407eeb34204a1df967b8fbe481cb04d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92905d020164683947943040ec19c530.png)
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6 . 在
中,内角
所对的边分别是
,若
,则
的面积是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfefacb6873f155f1f2d82010d43d8a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
A.4 | B.2 | C.![]() | D.![]() |
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7 . 在三棱锥
中,
平面
,
,
为边长等于
的正三角形,则三棱锥
的外接球的表面积是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b80ee363635d73f601654339028daec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c025ee3317be1099b7bf03a11e37ed4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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6卷引用:湖南省长沙市雅礼中学2023-2024学年高一下学期期中考试数学试题变式题6-10
(已下线)湖南省长沙市雅礼中学2023-2024学年高一下学期期中考试数学试题变式题6-10湖南省长沙市雅礼中学2023-2024学年高一下学期期中考试数学试题(已下线)专题13.8外接球与内切球3大题型13个方向-重难点突破及混淆易错规避(苏教版2019必修第二册)(已下线)6.6简单几何体的再认识-【帮课堂】(北师大版2019必修第二册)(已下线)模块三 易错点1 几何问题不会作辅助线(已下线)专题09 外接球、内切球与动点最值(1) -期末考点大串讲(苏教版(2019))
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8 . 如图,在四棱锥
中,底面
是正方形,
底面
,
,点
是
的中点,
于点
.
平面
;
(2)求二面角
的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10c83f8945042b9c8fb2fbdac9308d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a93767331e9bac06a564973a9f4fc663.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/defa5b53043ae802bb1af7d14374406d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f04e6ed01c8f3778a64f055d33ee70c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78307cd417504554a4e2276fe24d1162.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1885efcff0b903e314057dd153578600.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6772edef04d878a91bf4d7e8419a4628.png)
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8卷引用:湖南省长沙市雅礼中学2023-2024学年高一下学期期中考试数学试题变式题16-19
(已下线)湖南省长沙市雅礼中学2023-2024学年高一下学期期中考试数学试题变式题16-19湖南省长沙市雅礼中学2023-2024学年高一下学期期中考试数学试题(已下线)6.5.2平面与平面垂直-【帮课堂】(北师大版2019必修第二册)(已下线)模块三 易错点1 几何问题不会作辅助线(已下线)6.5.2 平面与平面垂直-同步精品课堂(北师大版2019必修第二册)(已下线)专题04 第八章 立体几何初步(2)-期末考点大串讲(人教A版2019必修第二册)重庆市朝阳中学2023-2024学年高一下学期5月月考数学试题江苏省宿迁市泗阳县两校联考2023-2024学年高一下学期第二次学情调研(5月月考)数学试题
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解题方法
9 . 在矩形
中,
,
,沿矩形对角线
将
折起形成四面体
.则在这个过程中,下列结论中正确的是()
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f8eeeea1c9652cacce976f8129cf520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
A.当![]() ![]() |
B.四面体![]() ![]() |
C.![]() ![]() ![]() |
D.四面体![]() |
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(已下线)湖南省长沙市雅礼中学2023-2024学年高一下学期期中考试数学试题变式题11-15湖南省长沙市雅礼中学2023-2024学年高一下学期期中考试数学试题吉林省长春市十一高中2023-2024学年高一下学期第二学程考试数学试题
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10 . 某班兴趣小组做了一次关于“电子产品对视力的影响”的问卷调查.他们从
岁,7~12岁,13~15岁,16~18岁四个年龄段回收的问卷依次为120份、180份、240份、
份.因调查需要,现从回收的问卷中按年龄段按比例分配分层随机抽取一个容量为300的样本.若在
岁年龄段的问卷中抽取了60份,则应在
岁年龄段的问卷中抽取的份数为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be43636ffbfa39006ff0f2cfd581220a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93b1256377f3924db5f950eedf7f06e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d02d5f1c57260185994579f082b54ace.png)
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