名校
1 . (1)已知
,
,
分别为
三个内角
,
,
的对边.请用向量方法证明等式
;
(2)若三个正数
,
,
满足
,证明:以
,
,
为长度的三边可以构成三角形.
![](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/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/34369422d71dd95c61cdd1b8245d7b6c.png)
(2)若三个正数
![](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/bba9192c300ab7108a36178e61a2d9c3.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)
您最近一年使用:0次
2023-07-15更新
|
362次组卷
|
2卷引用:湖南省长沙市雅礼中学2022-2023学年高二下学期期末数学试题
名校
解题方法
2 . 在棱长为2的正方体ABCD-A1B1C1D1中,M、N、Q、S分别是被AB、BC、C1D1、D1A1的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/9/3eda4dd4-002f-4937-97f9-a3ffff793ecc.png?resizew=163)
(1)求证:MN//QS;
(2)记MNQS确定的平面为α,作出平面α被该正方体所截的多边形截面,写出作法步骤.并说明理由,然后计算截面面积;
(3)求证:平面ACD1//平面α.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/9/3eda4dd4-002f-4937-97f9-a3ffff793ecc.png?resizew=163)
(1)求证:MN//QS;
(2)记MNQS确定的平面为α,作出平面α被该正方体所截的多边形截面,写出作法步骤.并说明理由,然后计算截面面积;
(3)求证:平面ACD1//平面α.
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解题方法
3 . 不等关系是数学中一种最基本的数量关系,生活中随处可见.例如:“已知b克糖水中含有a克糖(
),再添加m克糖(
)(假设全部溶解),糖水变甜了.”请将这一事实表示为一个不等式,并证明这个不等式成立.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d100c22435a23e017cfe6f535379d3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58b140e221ddf537b8964fff8557cca0.png)
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4 . 已知数列
满足:
,
.
(1)求数列
的通项公式及前
项和
;
(2)令
,
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b13a6e1d671215fc96e4bee3541d1096.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c56bce770d2dc71875026ee547826a13.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63d471926f7b27322d90c82b9ce21d3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(2)令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07c1c95104e4df46b2b8b4c2596e90e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6104772b28c8a71666c13b7ff3d0f920.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dba067ad5d03360fef97ff0a9e786cfc.png)
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解题方法
5 . 记
为正数数列
的前n项的和,已知
.
(1)证明:数列
是等差数列;
(2)求数列
的前n项之和.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78515a07797b245e751d0937e2cbb875.png)
(1)证明:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8050391385b496e9c059201e4f12600a.png)
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6 . 已知数列
满足
,且
.
(1)令
,求证:
是等比数列;
(2)求数列
的通项公式
及数列
的前
项和.
![](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/7a76fc5c4b88789bdcdd0825765bc4ca.png)
(1)令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3e290f06f8f75e5bbfec2d27c0c6e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
您最近一年使用:0次
2023-01-29更新
|
1116次组卷
|
2卷引用:河南省郑州励德双语学校2022-2023学年高二下学期第二次考试数学试题
名校
7 . △ABC中,a,b,c分别是角A,B,C的对边,
,
,
(1)求b的最大值;
(2)若△ABC的面积为
,求证:△ABC是直角三角形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8120119749d4bc28067e73fca7d46cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e899c486dc49e560fc4aca05e16835b7.png)
(1)求b的最大值;
(2)若△ABC的面积为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/860884c0017c8bceb5b0edff796c144f.png)
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2023-03-22更新
|
216次组卷
|
2卷引用:河北省邯郸市鸡泽县第一中学2022-2023学年高一下学期第一次月考数学试题
名校
解题方法
8 . 正三棱柱
的底面正三角形的边长为1,D为线段
上的动点,
.
(1)当D为
中点时,证明:
//平面
;
(2)当D在线段
上移动时,求
周长的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6db57eca2a7cbd91bc57372592580a76.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/14/7354bf80-7ebc-425f-94cf-ed73dc48eabf.png?resizew=195)
(1)当D为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ba9e20d667d04bf3ee7f55cc795ce01.png)
(2)当D在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fdd324f113250febd154c16648ac6533.png)
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9 . 为了求一个棱长为
的正四面体体积,小明同学设计如下解法:构造一个棱长为1的正方体,如图1:则四面体
为棱长是
的正四面体,且有
.学以致用:
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/13/7f6e930f-e5a9-4fb1-a52c-5d884c18416e.png?resizew=304)
(1)如图2,一个四面体三组对棱长分别为
,2,
,求此四面体外接球表面积;
(2)若四面体ABCD每组对棱长分别相等,求证:该四面体的四个面都是锐角三角形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68ac02c2f91cadb1e328bc6ab9b9c491.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff5e6b8c4de00d7e01238f7a32c19429.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/13/7f6e930f-e5a9-4fb1-a52c-5d884c18416e.png?resizew=304)
(1)如图2,一个四面体三组对棱长分别为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
(2)若四面体ABCD每组对棱长分别相等,求证:该四面体的四个面都是锐角三角形.
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解题方法
10 . 已知数列
中,
,且
.
(1)求
,并证明
是等比数列;
(2)求
的通项公式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/039e4fe671d61e59b96ee525c9df43e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2219ea8d05ddac5cc049b09e602ccb6a.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe61d313eeca8ba47478a9de40540db8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d483eb4433fee05a5810a276433b1742.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
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