解题方法
1 . 已知
的值域为
.
(1)求实数
的值;
(2)判断函数
在
上的单调性,并给出证明;
(3)若
,求证
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3be8c296dba4a6442f262437f6671c80.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a2ec965488c7e1cea085463c7731285.png)
(1)求实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9a475fec8ded321e10a6697319fb975.png)
(2)判断函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4f3966052d4a779b6247fdf12f97cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d188ec2580e273ce87e51653a2177ee.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9bf039c46a25e331446c6ee1e9af3c82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efb85ae535f90b3c125d86b439ab2562.png)
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2 . 已知罗尔中值定理:若函数
满足:①
在
上连续;②
在
上可异;③
,则存在
,使得
.
(1)试证明拉格朗日中值定理:若函数
满足:①
在
们上连续;②
在
上可导,则存在
,使得
.
(2)设
的定义域与值域均为
且
在其定义域上连续且可导.求证:对任意正整数n,存在互不相同的
,使得
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.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/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30277e0be448b4955903e81e8795e45d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f94345694d4215284c41f87146795ee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8166cc061d434d02bccbcf153cc6b48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be227e1da97582fd99cb7cec416982af.png)
(1)试证明拉格朗日中值定理:若函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.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/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30277e0be448b4955903e81e8795e45d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8166cc061d434d02bccbcf153cc6b48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7853db400c62dc688f01aa38be72acd2.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a61eaad9616cce2705245cc7ffc2636.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05eca773cea4fc8732050ab44063aa3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5932903a7ddb5fe53eff8249c6cd3619.png)
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解题方法
3 . 阅读下面题目及其证明过程,在
处填写适当的内容.
已知三棱柱
,
平面
,
,
分别为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/27/daabe3a8-f5d5-4b94-9577-eeb61c3f5b0f.png?resizew=135)
(1)求证:
∥平面
;
(2)求证:
⊥
.
解答:(1)证明: 在
中,
因为
分别为
的中点,
所以 ① .
因为
平面
,
平面
,
所以
∥平面
.
(2)证明:因为
平面
,
平面
,
所以 ② .
因为
,
所以
.
又因为
,
所以 ③ .
因为
平面
,
所以
.
上述证明过程中,第(1)问的证明思路是先证“线线平行”,再证“线面平行”; 第(2)问的证明思路是先证 ④ ,再证 ⑤ ,最后证“线线垂直”.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80d5d02301554aad6cc89452c83f0862.png)
已知三棱柱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62d77afb7d8280995886ff690e7a6c9a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/27/daabe3a8-f5d5-4b94-9577-eeb61c3f5b0f.png?resizew=135)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
解答:(1)证明: 在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f9e1e0d29bc4bdf0c6d38ca4db43343.png)
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62d77afb7d8280995886ff690e7a6c9a.png)
所以 ① .
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/871502ee0c5d1414cfe81e8409b62d76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f196748dc6a0d0bd9e9e4dd30ac4ed0e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)证明:因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be509ef5101aae24609ff9941cb246fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
所以 ② .
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
又因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5d970e34169fb0de8a3f10e4c6ae40d.png)
所以 ③ .
因为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6cb3896ef1afc6a56a5aa0243022e0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ac61c24f99a4e466f1e2ea011893866.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ba985fb50a9078a839b66bf1d1eadea9.png)
上述证明过程中,第(1)问的证明思路是先证“线线平行”,再证“线面平行”; 第(2)问的证明思路是先证 ④ ,再证 ⑤ ,最后证“线线垂直”.
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名校
4 . 如图1,AB为⊙O的直径,点P是直径AB上任意一点,过点P作弦
,垂足为P,过点B的直线与线段AD的延长线交于点F,且∠F=∠ABC.
![](https://img.xkw.com/dksih/QBM/2022/8/3/3036407790297088/3042341699436544/STEM/1f38f551e5a54e12bfa08392d396732b.png?resizew=302)
(1)若CD=
,BP=4,求⊙O的半径;
(2)求证:直线BF是⊙O的切线;
(3)当点P与点O重合时,过点A作⊙O的切线交线段BC的延长线于点E,在其它条件不变的情况下,判断四边形AEBF是什么特殊的四边形?请在图2中补全图象并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b757f0c42ae5c9a2d6a4b19e5877b27.png)
![](https://img.xkw.com/dksih/QBM/2022/8/3/3036407790297088/3042341699436544/STEM/1f38f551e5a54e12bfa08392d396732b.png?resizew=302)
(1)若CD=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38387ba1cadfd3dfc4dea4ca9f613cea.png)
(2)求证:直线BF是⊙O的切线;
(3)当点P与点O重合时,过点A作⊙O的切线交线段BC的延长线于点E,在其它条件不变的情况下,判断四边形AEBF是什么特殊的四边形?请在图2中补全图象并证明你的结论.
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5 . 某同学解答一道导数题:“已知函数f(x)=sinx,曲线y=f(x)在点(0,0)处的切线为l.求证:直线l在点(0,0)处穿过函数f(x)的图象.”
该同学证明过程如下:
证明:因为f(x)=sinx,
所以
.
所以
.
所以曲线y=f(x)在点(0,0)处的切线方程为y=x.
若想证直线l在点(0,0)处穿过函数f(x)的图象,
只需证g(x)=f(x)﹣x=sinx﹣x在x=0两侧附近的函数值异号.
由于g'(x)=cosx﹣1≤0,
所以g(x)在x=0附近单调递减.
因为g(0)=0,
所以g(x)在x=0两侧附近的函数值异号.
也就是直线l在点(0,0)处穿过函数f(x)的图象.
参考该同学解答上述问题的过程,请你解答下面问题:
已知函数f(x)=x3﹣ax2,曲线y=f(x)在点P(1,f(1))处的切线为l.若l在点P处穿过函数f(x)的图象,则a的值为( )
该同学证明过程如下:
证明:因为f(x)=sinx,
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/494bd23f6edc500cbc0fe04f7bd7515c.png)
所以
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a587fb0ee137864d8ecd72274540af38.png)
所以曲线y=f(x)在点(0,0)处的切线方程为y=x.
若想证直线l在点(0,0)处穿过函数f(x)的图象,
只需证g(x)=f(x)﹣x=sinx﹣x在x=0两侧附近的函数值异号.
由于g'(x)=cosx﹣1≤0,
所以g(x)在x=0附近单调递减.
因为g(0)=0,
所以g(x)在x=0两侧附近的函数值异号.
也就是直线l在点(0,0)处穿过函数f(x)的图象.
参考该同学解答上述问题的过程,请你解答下面问题:
已知函数f(x)=x3﹣ax2,曲线y=f(x)在点P(1,f(1))处的切线为l.若l在点P处穿过函数f(x)的图象,则a的值为( )
A.3 | B.![]() | C.0 | D.﹣3 |
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6 . 二次函数
为实数,对任意的
都有
和
恒成立.已知
的函数图象与
的图象有且只有一个公共点,这个公共点在第二象限.
(1)求证:
;
(2)若
的最小值为-10,求函数
的解析式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047b643568a5f86e592fc2f919cce0f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b273ec7bc43fbbd941d1817a3b841a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c12d98e7a7fef3b4100f52b6125f69b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f1d8d5cea065075fe50706abe3ae802.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5e9e27ed3ef92663617c2f2815e7025.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a302d9c6416963c881b884bf4e4d783.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
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7 . 如图,点
为
中点,分别延长
到点
到点
,使
.以点
为圆心,分别以
为半径在
上方作两个半圆.点
为小半圆上任一点(不与点
重合),连接
并延长交大半圆于点
,连接
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/14/1ddf5ce2-4468-4d8c-b5ec-b71201674b43.png?resizew=390)
(1)①求证:
;
②写出
和
三者间的数量关系,并说明理由.
(2)若
,当
最大时,直接指出
与小半圆的位置关系,并求此时
(答案保留
).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fa48616f1944739471d03422859b8e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33cbad6599796efc1c177ae9349feda9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8044faecc4d5a611814a7f1e64dbf8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abd13974aebe38eb2a1d744a01ea5aa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d6f0cb663c82fc5de837fa273f983ce8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/14/1ddf5ce2-4468-4d8c-b5ec-b71201674b43.png?resizew=390)
(1)①求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fb0368d6e9824a085e5b41c2da993d7.png)
②写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/497b955fd8c7d39a388ed329624d9bb0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b6aed6102edbc4138df13cba9c264b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/194741f4d2ae7ee44cafca780361446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/637f7d8b87adc59c9b06b09803a06553.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70f5389990c3a0c5373f3bd9fb2454c9.png)
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名校
8 . 下面结论正确的是( )
A.函数![]() ![]() |
B.数学归纳法证明![]() ![]() ![]() ![]() ![]() |
C.在二项式![]() ![]() |
D.已知等差数列![]() ![]() ![]() ![]() ![]() |
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名校
9 . 已知
为锐角
的高,
为
中点,
于点
,延长
至
,使得
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/20/251ad998-628d-454f-80c5-258fbecb0d07.png?resizew=161)
(1)证明:
;
(2)证明:
;
(3)若
,求四边形
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3c65edad25ddd666cdce0d7e5afefc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32c38dfd14dde969702dff97ef2270f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21037e170bdbb322558e79c40c00b454.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0792d20f1b18cc0367c8a3ce5492296.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/20/251ad998-628d-454f-80c5-258fbecb0d07.png?resizew=161)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/023bbaa6d993d5653a70ef88342daabe.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26910bb351f9cc7a34b1b69944c6d8b8.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61fbda9345c1cb562da40da144ca834d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61510c34c5795d7261569b4d09098271.png)
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10 . 已知
都是正实数,且
.
(1)证明:
必在
和
之间;
(2)请问:
和
这两个数,哪一个更接近于
,说明你的理由;
(3)请你再写出一个式子,使得它的值比
和
的值更接近于
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b39ad04a78e7320dfb3c2580038cff38.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3040f7e4e03a1a0a3449b89de5e2bccd.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a507c062709cfe2f218896247461c7d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb8b95ed19aea7c9641804b19966a0fd.png)
(2)请问:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a507c062709cfe2f218896247461c7d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb8b95ed19aea7c9641804b19966a0fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
(3)请你再写出一个式子,使得它的值比
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a507c062709cfe2f218896247461c7d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb8b95ed19aea7c9641804b19966a0fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
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