名校
解题方法
1 . 设实系数一元二次方程
①,有两根
,
则方程可变形为
,展开得
②,
比较①②可以得到![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71e360b7ba27dfc3e5d401027d5bd8a5.png)
这表明,任何一个一元二次方程的根与系数的关系为:两个根的和等于一次项系数与二次项系数的比的相反数,两个根的积等于常数项与二次项系数的比.这就是我们熟知的一元二次方程的韦达定理.
事实上,与二次方程类似,一元三次方程也有韦达定理.
设方程
有三个根
,则有
③
(1)证明公式③,即一元三次方程的韦达定理;
(2)已知函数
恰有两个零点.
(i)求证:
的其中一个零点大于0,另一个零点大于
且小于0;
(ii)求
的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c3f3db6b7c682450309a6ccba5ac5a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ce7ae90d808f05e86ea063238e4b2f9.png)
则方程可变形为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/455d33fcfd9a59d6b374e9d25888cd2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e42b42152492cbdfec62c7a02be4055.png)
比较①②可以得到
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71e360b7ba27dfc3e5d401027d5bd8a5.png)
这表明,任何一个一元二次方程的根与系数的关系为:两个根的和等于一次项系数与二次项系数的比的相反数,两个根的积等于常数项与二次项系数的比.这就是我们熟知的一元二次方程的韦达定理.
事实上,与二次方程类似,一元三次方程也有韦达定理.
设方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ddc5e3c2c7c6f4d2d0ab396b65679a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05b8ec9d4206ea66a02de5c4a1e1e911.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb8d75a2417827b2c5b09ba9385fe252.png)
(1)证明公式③,即一元三次方程的韦达定理;
(2)已知函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2b5e4746c2bd0afb279630698afd3a0.png)
(i)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d275fbb3ee5cd1177ca5a2ceecbbef0f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274a9dc37509f01c2606fb3086a46f4f.png)
(ii)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20d6fc9b90f370fbb27552876b650f8f.png)
您最近一年使用:0次
解题方法
2 . 已知椭圆
:
的离心率为
,且过点
.
(1)求
的方程;
(2)直线
:
与椭圆
分别相交于
,
两点,且
,点
不在直线
上:
(I)试证明直线
过一定点,并求出此定点;
(II)从点
作
垂足为
,点
,写出
的最小值(结论不要求证明).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48da128547c4cf9745e8e4b99988a3db.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/860884c0017c8bceb5b0edff796c144f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c179fe7eff7abfdd092b63c9c1b82d0c.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15b256345d7109e081b7c895591e995d.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/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f59747cee312ee5140643428cae79efa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
(I)试证明直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
(II)从点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7920d2550a6af7df3db60a33fe02c53b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/107b446164f491149461baefded6f18a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76a0abdf3eea0772418890031971fb56.png)
您最近一年使用:0次
名校
解题方法
3 . 如图,四棱锥
中,
,
,
为
的中点.
平面
.
(2)在线段
上是否存在一点
,使得平面
平面
?若存在,证明你的结论,若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12143a06ed24558d8cc7ad39961d3e1f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/932a04304f2d4975955d4baabb2deeea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b711c453131b5420cbade7e0e451b908.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6261790c66cc71ee3898afabad0c09f4.png)
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2022-09-14更新
|
2235次组卷
|
19卷引用:贵州省毕节市七星关区海子街中学2018-2019学年高二下学期期末考试数学(文)试题
贵州省毕节市七星关区海子街中学2018-2019学年高二下学期期末考试数学(文)试题安徽省马鞍山市第二中学2020-2021学年高二上学期期末文科数学试题安徽省巢湖市黄山中学2019-2020学年高二上学期第一次月考文科数学试题四川省峨眉文旅综合高中学校2022-2023学年高二上学期第一次月考数学试题(已下线)第03讲 空间中平行、垂直问题10种常见考法归类(2)福建省南平市建瓯市芝华中学2019-2020学年高一上学期期中(B)卷数学试题(已下线)专题8.3 直线、平面平行的判定与性质-2021年高考数学(理)一轮复习-题型全归纳与高效训练突破(已下线)专题8.3 直线、平面平行的判定与性质-2021年高考数学(文)一轮复习-题型全归纳与高效训练突破(已下线)第31练 直线、平面平行的判定与性质-2021年高考数学(理)一轮复习小题必刷(已下线)考点47 直线与平面、平面与平面平行-备战2022年高考数学一轮复习考点帮(新高考地区专用)【学科网名师堂】(已下线)第47讲 直线与平面、平面与平面平行(已下线)高考新题型-立体几何初步(已下线)8.5 空间直线、平面的平行(精练)-2022-2023学年高一数学一隅三反系列(人教A版2019必修第二册)(已下线)8.5.3 平面与平面平行 (精讲)(1)-【精讲精练】2022-2023学年高一数学下学期同步精讲精练(人教A版2019必修第二册)(已下线)8.5.3 平面与平面平行(精讲)-【题型分类归纳】2022-2023学年高一数学同步讲与练(人教A版2019必修第二册)天津市西青区杨柳青第一中学2022-2023学年高一下学期第二次适应性测试(期中)数学试题福建省福州市闽侯县第一中学2022-2023学年高一下学期5月月考数学试题(已下线)专题6-3立体几何大题综合归类-2(已下线)专题突破:空间几何体的动点探究问题-同步题型分类归纳讲与练(人教A版2019必修第二册)
名校
解题方法
4 . 如图,四棱锥P-ABCD的底面ABCD是菱形,PA⊥AB,PA⊥AD,且E、F分别是AC、PB的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/14/69dda575-4b41-45c5-935a-6aa6fca009ce.png?resizew=160)
(1)证明:EF∥平面PCD;
(2)求证:平面PBD⊥平面PAC.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/14/69dda575-4b41-45c5-935a-6aa6fca009ce.png?resizew=160)
(1)证明:EF∥平面PCD;
(2)求证:平面PBD⊥平面PAC.
您最近一年使用:0次
2022-04-26更新
|
1073次组卷
|
3卷引用:贵州省遵义市第四中学2021-2022学年高二上学期期末质量监测数学试题
5 . 在数列
中,
,
(
).
(1)求
,
,
;
(2)猜想
;并加以证明;
(3)若数列
,设数列
的前
项和
.求证
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b065334d8f60c49f4bd3d9f1373fe4cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e76a35065ee95d9a308d2b439fc57f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e88093a749c0d46e0ee931ecfaff925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c1ccc6c74b8754e9bcbb3f39a11b6f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
(2)猜想
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
(3)若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/980d51ba3340a31964fbec9e6f243ca6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbbb29ff6c20c4d5fd2cb319eb191d77.png)
您最近一年使用:0次
6 . (1)已知
是实数,求证:
.
(2)用分析法证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69d21cedbf84856328405de3bf6275ba.png)
(2)用分析法证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/14c19d94ff48082c1cd213c82c99abf0.png)
您最近一年使用:0次
2020-08-04更新
|
107次组卷
|
10卷引用:贵州省兴仁市凤凰中学2019-2020学年高二下学期第一次月考数学(理)试题
贵州省兴仁市凤凰中学2019-2020学年高二下学期第一次月考数学(理)试题贵州省兴仁市凤凰中学2019-2020学年高二下学期第一次月考数学(文)试题江西省山江湖协作体2019-2020学年高二上学期第三次月考(统招班)数学(文)试题安徽省蚌埠二中2019-2020学年高二下学期开学检测文科数学试题安徽省淮南一中2020-2021学年高二下学期第一次段考理科数学试题(已下线)2.2.1 直接证明-2020-2021学年高二数学(理)课时同步练(人教A版选修2-2)山西省怀仁市大地学校2020-2021学年高二下学期第三次月考数学(理)试题山西省怀仁市大地学校2020-2021学年高二下学期第三次月考数学(文)试题(已下线)专题23 不等式选讲-2020年高考数学(理)母题题源解密(全国Ⅲ专版)(已下线)专题23 不等式选讲-2020年高考数学(文)母题题源解密(全国Ⅲ专版)
7 . (1)用数学归纳法证明:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f255b619288af6e02608279ea909a51d.png)
(2)用反证法证明:已知
,且
,求证
中至少有一个大于1.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f255b619288af6e02608279ea909a51d.png)
(2)用反证法证明:已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dcbca3478eae63853d2aab5332e2e56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f9e131cdd242d56b6dba05ab3363ef3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
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名校
8 . 已知二次函数
(
均为实数),满足
,对于任意实数
都有
,并且当
时,有
.
(1)求
的值;并证明:
;
(2)当
且
取得最小值时,函数
(
为实数)单调递增,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1bd0587f5d6a3b5db9e4a93e0dbc0ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c766352f0be38b719621052de92615bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fffcb16e0156bb695b6f97b5c654661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff133c17652425c22f0b367e002797df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd53e5d21d735d3d2dfb6ee01ec2650c.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74156327e5659301f391814605688899.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f17d9b0379b2b27da73d525d61de9093.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75bde2e500fd5386e355db9040a1946d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd1810555c0c28fe352841322b85bbc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/461d9ebddd8fd839073485e9dc113256.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/434e938638cced59180fb39abbf78b95.png)
您最近一年使用:0次
2017-09-02更新
|
51次组卷
|
2卷引用:贵州省铜仁一中2016-2017学年高二下学期期末数学(文)试题
9 . 如图,四棱锥
的底面是正方形,侧棱
⊥底面
是
的中点.
(Ⅰ)求证:
∥
;
(Ⅱ)证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8f449e8cd3075c1de5cae3a57293f38.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f6d94889ef44776a1a60586922ee891.png)
(Ⅱ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/509d8dd6031dc0ef92075877e53fe201.png)
![](https://img.xkw.com/dksih/QBM/2017/11/15/1817625011290112/1819374978760704/STEM/dc9e51a78fac47e59bc20c1aae79dcbe.png?resizew=166)
您最近一年使用:0次
2017-11-17更新
|
936次组卷
|
5卷引用:北京师范大学遵义附属学校2020-2021学年高二第一学期期中考试数学试卷
10 . 已知
为数列
的前
项和,
,且
.
(1)证明数列
是等差数列,并求其前
项和
;
(2)设数列
满足
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/759caa9a3df7c8381f6600ed3143afdf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69c7266d90661cf4467f13c6f5eb670c.png)
(1)证明数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4be2164a2c67d6163faee87a10942bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(2)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43b7e7cd571c8cd141cbbfe5d0890bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5a28cd035abe6bbf35f7d2b50eb917b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/803608cc91af54afd734afadfd894245.png)
您最近一年使用:0次