名校
1 . 根据多元微分求条件极值理论,要求二元函数
在约束条件
的可能极值点,首先构造出一个拉格朗日辅助函数
,其中
为拉格朗日系数.分别对
中的
部分求导,并使之为0,得到三个方程组,如下:
,解此方程组,得出解
,就是二元函数
在约束条件
的可能极值点.
的值代入到
中即为极值.
补充说明:【例】求函数
关于变量
的导数.即:将变量
当做常数,即:
,下标加上
,代表对自变量x进行求导.即拉格朗日乘数法方程组之中的
表示分别对
进行求导.
(1)求函数
关于变量
的导数并求当
处的导数值.
(2)利用拉格朗日乘数法求:设实数
满足
,求
的最大值.
(3)①若
为实数,且
,证明:
.
②设
,求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4a1d0dba29a77dd111efcde543d6c1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc4c14935585e8fa61d032730867d771.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67b6f154c6b2de5695eb1807b98c2c63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/809615d1f91508e2c6c0cda7e592c479.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/244021f826099b18e31af1143597bba2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb5be11a5e6aaf00b2833930b198b4cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0203b006524305c3d8ee0b6c34cd872b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4a1d0dba29a77dd111efcde543d6c1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc4c14935585e8fa61d032730867d771.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1c3c1ed4fb65ab9505ad8078d8d0fb5.png)
补充说明:【例】求函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d7ca0caa9933b7afd4bed2683140a07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aebdee8d81b048b5aa520f7e8ba56ff2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1e15a54c6122c695239107dd0901bc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/244021f826099b18e31af1143597bba2.png)
(1)求函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b3d9ab2fcf15b94f33cb64f84ed906c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b384412acba251d87902ab928902f16.png)
(2)利用拉格朗日乘数法求:设实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c45d8122b61de13875003d00c002c5b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de725a9fc66f67abbe0015131846a648.png)
(3)①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a14c388e1e2e5a2ff1ccf6caffbee0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd24c686fbaaa68705d654b880481ffe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e778f95c72fec00bfbbc63e6dfd0c460.png)
②设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/497d269c30eec393e3f0e877ddbe2983.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ade042c085bbad8aeaf111b9f4c33408.png)
您最近一年使用:0次
名校
解题方法
2 . 设
则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a766cb386e733f9cbb2bc787a9477c8b.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次
名校
解题方法
3 . 记
的内角
,
,
所对的边分别为
,
,
.已知向量
,
.
(1)设单位向量
,若
与
共线,且
,求
;
(2)当
时:
(i)若
,求
;
(ii)求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6849215c180ffa7aed5695cfe5169c61.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/309fc14fb3c33dd3532a3823019d7d70.png)
(1)设单位向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e66a1639eb1a8f7e8e23e67c246f3b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea48f17ea5a7459bc77626ef7aa44b89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c37564ec4e9e92485f1769e8ffaac31d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a36ec31cfd615abfbee3ed2f4a1d8883.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a4d070c5939bb0ec4a9d40d7e3c7d3f.png)
(i)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3711c8ba16405959bcb0b70385da1d89.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
(ii)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/413323ab92f73c1eabb235731bb5c399.png)
您最近一年使用:0次
2024-03-25更新
|
944次组卷
|
3卷引用:河北省衡水市枣强中学2023-2024学年高一下学期第二次调研考试数学试题
河北省衡水市枣强中学2023-2024学年高一下学期第二次调研考试数学试题(已下线)第13题 解三角形与其他知识的交汇(高一期末每日一题)广东省深圳市深圳外国语学校理工高中2023-2024学年高一下学期3月调研考试数学试卷
解题方法
4 . 已知椭圆
的左、右焦点分别为
、
,离心率为
.点
在直线
上运动,且直线
的斜率与直线
的斜率之商为2.
(1)求
的方程;
(2)若点A、B在椭圆
上,
为坐标原点,且
,求
面积的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad523e69a1bf925e73a22900b9855df2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/346d7171f852465998210d138ceca96d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b67528f875a6d4bac8bbf784f7b66a0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/183b6a0cef4256c9696a5bca31053da5.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)若点A、B在椭圆
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3825ccc273ef9a672a606432d165b866.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/866b81a8384cce4f24867baca2e6820c.png)
您最近一年使用:0次
5 . 已知抛物线
的焦点为
,过
作两条互相垂直的直线
,
与
交于
、Q两点,
与
交于
、N两点,
的中点为
的中点为
,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1bb4dd4670828f75bc573b52cdd02e1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b270384ef6e4041b44aa962a788657fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5d27c081879b6c6bc0abb0ceedb9d3a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f6f17bc385bafb37e8f964e5eb99cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a5f1641947153c80b987320885a2b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2058c7978c1bd12ed2ee293046c5e2ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
A.当![]() ![]() | B.![]() |
C.直线![]() ![]() | D.![]() |
您最近一年使用:0次
名校
6 . 如图,已知点
是边长为1的正三角形
的中心,线段
经过点
,并绕点
转动,分别交边
于点
,设
,其中
.
的值;
(2)求
面积的最小值,并指出相应的
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dec2ca6438c82b43f746057d8129885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ed96677f96685494302fd7fc0762047.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5ca1fae322fcf42507a35892a86aeeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d27e62ba44cbfec6823ebc1f0c7457fb.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/280860dd039e1305a5ccc455f63e8223.png)
您最近一年使用:0次
2024-03-23更新
|
2948次组卷
|
11卷引用:1号卷·A10联盟2022届全国高考第一轮总复习试卷数学(文科)试题(十)
1号卷·A10联盟2022届全国高考第一轮总复习试卷数学(文科)试题(十)重庆市九龙坡区部分学校2023-2024学年高一下学期阶段测试数学试题(已下线)考点1 平面向量的概念及线性运算 --2024届高考数学考点总动员【练】(已下线)第六章 本章综合--方法提升应用【第三练】“上好三节课,做好三套题“高中数学素养晋级之路(已下线)2.4 平面向量基本定理及坐标表示-同步精品课堂(北师大版2019必修第二册)山西省朔州市怀仁市第一中学校2023-2024学年高一下学期第二次月考(3月)数学试题(已下线)2.4 平面向量基本定理及坐标表示6种常见考法归类(2)-【帮课堂】(北师大版2019必修第二册)福建省漳州市云霄第一中学2023-2024学年高一(平行班)下学期第一次月考数学试题重庆市部分学校2023-2024学年高一下学期第一次月考数学试卷甘肃省天水市第一中学2023-2024学年高一下学期4月月考数学试题黑龙江省双鸭山市第一中学2023-2024学年高一下学期4月月考数学试题
名校
解题方法
7 . 四边形ABCD中,
,
,
,设△ABD与△BCD的面积分别为
,
,则
的最大值为______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/714cc3707bba3bfdb56e251999be8592.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0922d3d0ca05ee8f4ea564cdf772e99.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cbeb8ebe198bb9ef37b5c57027b28821.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e097c8d4c948de063796bd19f85b3a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e0bd63f55069a3bc870915010b39225.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/50524aaa1503092bd18419de6d851541.png)
您最近一年使用:0次
2024-03-22更新
|
1087次组卷
|
4卷引用:河南省郑州市名校教研联盟2024届高三下学期模拟预测数学试卷
河南省郑州市名校教研联盟2024届高三下学期模拟预测数学试卷老华大联盟2024届高三下学期3月联考文科数学试卷(全国乙卷)(已下线)第13题 解三角形压轴小题(二轮每日一题)(已下线)【练】专题4 解三角形的范围(最值)问题(压轴小题)
8 . 已知
为抛物线
的焦点,过直线
上的动点
作抛物线的切线,切点分别是
,则
与
为坐标原点)面积之和的最小值为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb5725b1ee742f2ae12a2dcf9839e172.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58fbf5b4a5543013296ff7e90ce24124.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6bce3d91ca23b86d8c6625f2632e437.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28dfc72e3ecc3e042e3a9582935af07a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/453e179570ed2bf55400cf5eed83cec4.png)
您最近一年使用:0次
名校
9 . 已知
中,边
上的高为
,
为
上一动点,满足
,则
的最小值是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0347a2dbf5fba623d097cb892fa8946.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6d831223c3c4ae2ee718118f97a06d6.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
名校
解题方法
10 . 以
表示数集
中最大(小)的数.设
,已知
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b09a461c487b39c41cff456cfedf744.png)
__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d660c6f3af62c625f87645d15a069198.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/846fed98a219097783e0ca2f41483cac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3385802ec776d5782adc6bfb0807246.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b09a461c487b39c41cff456cfedf744.png)
您最近一年使用:0次