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解题方法
1 . 某水果店每天进货草莓200斤,每斤草莓售价15元,可以全部售完:如果草莓定价15.5元,则只能售出190斤,每斤每涨0.5元,销售量就会减少10斤,剩余的草莓在第二天以每斤10元的价格可以便宜出售并全部售完.如何给草莓定价,能使这批草莓销售金额最高.
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2 . 如果
,那么
,
的值为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5da464ce264ba6b775d5bc68a3cc223a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
A.1,![]() | B.![]() ![]() | C.7,![]() | D.![]() ![]() |
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3 . 已知________.
(1)解不等式
;
(2)若
的解集为R,求实数b的取值范围.
从下面条件①、条件②中任选一个,补充在上面的横线上作为已知,并作答.
①
的最小值是a;
②不等式
的解集是
.
(1)解不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0de9db115080b62ceb32d39f890b6d8f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c93a5df4808c014f0b4aeffefb3d05e.png)
从下面条件①、条件②中任选一个,补充在上面的横线上作为已知,并作答.
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/222d0ba81e913f1289c10e4783ce35db.png)
②不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce9a91332440ae5eb3495cbc4cbd64b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0b05849c5aa6777c65d0035f08ad96e.png)
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解题方法
4 . 设
,
,
,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ef2a45773db8d347f0cfa4e4fca7fd5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b486d6d9a855a8cf9ee2c69c04ae8ad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8add3bac16eaf09b04d5a976828a561.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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2023-01-13更新
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562次组卷
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6卷引用:北京市陈经纶中学2022-2023学年高一上学期12月诊断数学试题
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5 . 已知数列
,
,
,
满足
且
,2,
,
,数列
,
,
,
满足
,2,
,
,其中
,
,2,
,
表示
,
,
,
中与
不相等的项的个数.
(1)数列
,1,2,3,4,请直接写出数列
;
(2)证明:
,2,
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/713ac1eb0d8cce55d51e62ef4a2b1634.png)
(3)若数列A相邻两项均不相等,且
与A为同一个数列,证明:
,2,
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/140b9dbcada4ac2e5fe3cc30009bcd67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07096af3b99fd1cb11c31f19a2c6408e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84390c669bd7a961e2161106903fa103.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e61e241c6c220b3b4705a8c1a465d7b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92e99796887e62d6de33cead5e11c00e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07096af3b99fd1cb11c31f19a2c6408e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/713ac1eb0d8cce55d51e62ef4a2b1634.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f17923637012a75a01f309379c1909c2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13423c094861baf4b759b7f3d8c3c226.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07096af3b99fd1cb11c31f19a2c6408e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a54d5182f8520bfd9e225d835e924bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/790aeea3e93a2565637c6e0a41bc8ec9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07096af3b99fd1cb11c31f19a2c6408e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/713ac1eb0d8cce55d51e62ef4a2b1634.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87d50740801f1809b06dad5152558069.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe0befe2083a287274113203f5ed6f3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07096af3b99fd1cb11c31f19a2c6408e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/713ac1eb0d8cce55d51e62ef4a2b1634.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e72adb45c60c2f63b46e65ff787302bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07096af3b99fd1cb11c31f19a2c6408e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/668d1dcf486145a68016aab72dc6a4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50a272adba0f1120109824440f0e252c.png)
(1)数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f344a2d8d76fad8cbecaffc44f11f907.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfe59c8f17cdb81bf5305909fa137d32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07096af3b99fd1cb11c31f19a2c6408e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/713ac1eb0d8cce55d51e62ef4a2b1634.png)
(3)若数列A相邻两项均不相等,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0157ed29461c0c3559684b07c381a0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07096af3b99fd1cb11c31f19a2c6408e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/713ac1eb0d8cce55d51e62ef4a2b1634.png)
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2023-01-11更新
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437次组卷
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2卷引用:北京市第二中学2021-2022学年高二下学期期末数学试题
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6 . 根据国家高考改革方案,普通高中学业水平等级性考试科目包括政治、历史、地理、物理、化学、生物6门,考生可根据报考高校要求和自身特长,从6门等级性考试科目中自主选择3门科目参加考试,在一个学生选择的三个科目中,若有两个或三个是文史类(政治、历史、地理)科目,则称这个学生选择科目是“偏文”的,若有两个或三个是理工类(物理、化学、生物)科目,则称这个学生选择科目是“偏理”的.为了了解同学们的选课意向,从北京二中高一年级中随机选取了20名同学(记为
,
,2,
,19,20其中
是男生,
是女生),每位同学都各自独立的填写了拟选课程意向表,所选课程统计记录如表:
(1)从上述20名同学中随机选取3名同学,求恰有2名同学选择科目是“偏理”的概率;
(2)从北京二中高一年级中任选两位同学,以频率估计概率,记
为“偏文”女生的人数,求
的分布列和数学期望;
(3)记随机变量
,样本中男生的期望为
,方差为
;女生的期望为
,方差为
,试比较
与
;
与
的大小(只需写出结论).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50a272adba0f1120109824440f0e252c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7c45176df950dfe48b8ca7eac08ee349.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f782d70309802445202487eee751cbdd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dc8086120dd40f8b841f0e3d674fd68.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e266dafb2e8d23f1a572abc1be2a96fd.png)
学生科目 | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() | ![]() |
政治 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||
历史 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||
地理 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | ||||||||||
物理 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||
化学 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | |||||||||||
生物 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
(2)从北京二中高一年级中任选两位同学,以频率估计概率,记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f022950e0faa45b617d497b01b5292b9.png)
(3)记随机变量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2af47421c0539033d70024966f39835.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0924ce3e7d756f9f222752c9db8fb6af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a961e29b5b0773f3fdb8cc7e2ceb8094.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64bad212e1d9b641464ff6178109167e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/517ff073109a22fb321274d83412ebee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0924ce3e7d756f9f222752c9db8fb6af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64bad212e1d9b641464ff6178109167e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a961e29b5b0773f3fdb8cc7e2ceb8094.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/517ff073109a22fb321274d83412ebee.png)
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780次组卷
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6卷引用:北京市第二中学2021-2022学年高二下学期期末数学试题
北京市第二中学2021-2022学年高二下学期期末数学试题北京市海淀区中国人民大学附属中学2023届高三下学期开学摸底练习数学试题北京市人大附中2023届高三下学期2月开学考数学试题北京市广渠门中学2024届高三上学期开学考数学试题(已下线)7.3.2离散型随机变量的方差(分层作业)-【上好课】2022-2023学年高二数学同步备课系列(人教A版2019选择性必修第三册)(已下线)7.3.2 离散型随机变量的方差——课后作业(巩固版)
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7 . 下列叙述中,
①等差数列
,
为其前n项和,若
,
,则当
时,
最小;
②等差数列
的公差为d,前n项和为
,若
,则
为递增数列;
③等比数列
的前n项和为
,若
,则
有最小项;
④在等差数列
中,记
,若存在
,使得
,则
为递增数列.
正确说法有______ (写出所有正确说法的序号)
①等差数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b134439819d3069da709979cb9b1a991.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5846713aaecbab35ad985cbe9ad7d44a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd6cd3173d146902c5518503888c3b59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
②等差数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4ce64685821c3e55c07f151996ca8c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/846fa57d92d6ad44d6a0cafad1e71ed4.png)
③等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba5c8a6c196890aa7871ea0c82061ea5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/846fa57d92d6ad44d6a0cafad1e71ed4.png)
④在等差数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134aefab10d3e81e223e9123da5f417e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f29c06a3e9a73e905eb87d71efa201c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbb50854126e66c09294192ed1db29ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
正确说法有
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8 . 香农定理是通信制式的基本原理.定理用公式表达为:
,其中
为信道容量(单位:
),
为信道带宽(单位:
),
为信噪比.通常音频电话连接支持的信道带宽
,信噪比
.在下面四个选项给出的数值中,与音频电话连接支持的信道容量
最接近的值是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74c21280da5add920dff0e366a46bf79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d787ef00aad66473daeb31bd3b65bf0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72bc766cbead9ec6fb613abe669b0be2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60c91fa27331e9958df48fd5633432e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4127daf7bda6bd8eda3ca8edd6476979.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdddac11848fa96bd1670b77188a0f5e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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2023-01-04更新
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200次组卷
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3卷引用:北京市密云区2022-2023学年高一上学期(12月)数学期末试题
北京市密云区2022-2023学年高一上学期(12月)数学期末试题安徽省马鞍山市第二中学2022-2023学年高一下学期开学考试数学模拟试题(1)(已下线)河南省济源市、平顶山市、许昌市2022届高三文科数学试题变式题1-5
名校
解题方法
9 . 如图,在四棱锥
中,四边形
是平行四边形,点F为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/97ce03fd-4ef3-4ff4-9b7e-57a3d437e222.png?resizew=210)
(1)已知点G为线段
的中点,求证:CF∥平面
;
(2)若
,直线
与平面
所成的角为
,再从条件①、条件②、条件③这三个条件中选择几个作为已知,使四棱锥
唯一确定,求:
(ⅰ)直线
到平面
的距离;
(ⅱ)二面角
的余弦值.
条件①:
平面
;
条件②:
;
条件③:平面
平面
.
![](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/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/5/97ce03fd-4ef3-4ff4-9b7e-57a3d437e222.png?resizew=210)
(1)已知点G为线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c4180c271831327644dc83240b715b5.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83a04565a8ebaa111894b724b0ba266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
(ⅰ)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20af148464904e21f4374cc8fb886fba.png)
(ⅱ)二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a38a3e226347af68d7b15295342e209.png)
条件①:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
条件②:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9c3ec174b1ce835cc8737ff6ce57e52.png)
条件③:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
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2023-01-04更新
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951次组卷
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5卷引用:北京市西城区北师大二附中2022-2023学年高二上学期12月月考数学试题
北京市西城区北师大二附中2022-2023学年高二上学期12月月考数学试题北京市海淀区2022-2023学年高二上学期期末练习数学试题北京市中央民族大学附属中学2022-2023学年高二上学期期末数学试题(已下线)北京市海淀区2023届高三上学期期末练习数学试题变式题16-21河南省郑州市第一〇二高级中学2023-2024学年高二上学期10月月考数学试题
名校
10 . “天问一号”是执行中国首次火星探测任务的探测器,该名称源于屈原长诗《天问》,寓意探求科学真理征途漫漫,追求科技创新永无止境.图(1)是“天问一号”探测器环绕火星的椭圆轨道示意图,火星的球心是椭圆的一个焦点.过椭圆上的点P向火星被椭圆轨道平面截得的大圆作两条切线
,则
就是“天问一号”在点P时对火星的观测角.图(2)所示的Q,R,S,T四个点处,对火星的观测角最大的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ec8858389f4c3156a946ba8bf0d8a7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c45a8a837c11c07073da3ff751d70278.png)
A.Q | B.R | C.S | D.T |
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2023-01-04更新
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7卷引用:北京市西城区北师大二附中2022-2023学年高二上学期12月月考数学试题