1 . “角股猜想”是“四大数论世界难题”之一,至今无人给出严谨证明.“角股运算”指的是任取一个自然数,如果它是偶数,我们就把它除以2,如果它是奇数,我们就把它乘3再加上1.在这样一个变换下,我们就得到了一个新的自然数.如果反复使用这个变换,我们就会得到一串自然数,该猜想就是:反复进行角股运算后,最后结果为1.我们记一个正整数
经过
次角股运算后首次得到1(若
经过有限次角股运算均无法得到1,则记
),以下说法有误的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99cebc0b8a5e503e1e24cb57dbbde5b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0a1ae2246dcd710cf913417406c2efa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aeadb619367f955549a75a4eeb931011.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8a66dd357f643ef976d14e097446fcf.png)
A.![]() ![]() |
B.![]() |
C.对任意正整数![]() ![]() |
D.![]() ![]() |
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名校
2 . 下列语句是命题的是( )
A.二次函数的图象太美啦! | B.这是一棵大树 |
C.求证:![]() | D.3比5大 |
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3 . 设
为实数,定义
生成数列
和其特征数列
如下:
(i)
;
(ii)
,其中
.
(1)直接写出
生成数列的前4项;
(2)判断以下三个命题的真假并说明理由;
①对任意实数
,都有
;
②对任意实数
,都有
;
③存在自然数
和正整数
,对任意自然数
,有
,其中
为常数.
(3)从一个无穷数列中抽出无穷多项,依原来的顺序组成一个新的无穷数列,若新数列是递增数列,则称之为原数列的一个无穷递增子列.求证:对任意正实数
生成数列
存在无穷递增子列.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1010846eeec6c9da29640f5aa3f8738.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/796bb39a2ab23cfdb6e463ab30a7af2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4758b555ca9b157cc074f1e4a092e34a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f61c0bb2370087736c8e00e108b48c8.png)
(i)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20c051dc675bcca6a8f70a3dbe922354.png)
(ii)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3121951a9b059eef49b4a346d3aa2b94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c400b893304c51631873ded41027cf48.png)
(1)直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4e0c84de10f0f2186313169c3dc997b.png)
(2)判断以下三个命题的真假并说明理由;
①对任意实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81fbdf49cd00af1ff87259836ddd9f6b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/508cd31480a898a71472e2d5d22377c7.png)
②对任意实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81fbdf49cd00af1ff87259836ddd9f6b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19c99515d9952f2f7739fd750a31128f.png)
③存在自然数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a178f2c27906fc74afee1b7d7d52746.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1563da7b0f046a469476668a3686e8f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f59a60eb4d63ebc879ae5c26413bcdcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(3)从一个无穷数列中抽出无穷多项,依原来的顺序组成一个新的无穷数列,若新数列是递增数列,则称之为原数列的一个无穷递增子列.求证:对任意正实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da069077c220af26b9e77b02baeee4a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4758b555ca9b157cc074f1e4a092e34a.png)
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名校
4 . 课上我们学习了“
”符号和数学上陈述句
一些常用的否定形式
,实际上“若
,则
”为假命题可以表述为“至少存在特例
满足性质
,使
”,即我们常说的举反例.
(1)请利用上述逻辑语言说明以下两个命题为假:
①任何集合都不是空集的子集;②若
,则
;
(2)其他教材中有这样一种新命题的表述: 如果把命题“若
,则
”称为原命题,那么将其结论的否定作为条件,将其条件的否定作为结论,可以得到一个新命题“若
,则
”,我们称新命题为原命题的逆否命题.并且有一个非常强有力的结论:原命题与它的逆否命题是同真或同假的.请综合利用上述知识证明:对于正实数
,若
,则
;
(3)证明:原命题“若
,则
”与它的逆否命题“若
,则
”同为真命题或同为假命题.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ef73aff3fe470e367f4af24fdfff3df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d1c79d9d4f43ffb42f22c287058b5f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2303430b989c36a0c5380d64b3182690.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f2c566d4285f887b69c855f31849542.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e31113e042661f75628af5e3b2dc56f1.png)
(1)请利用上述逻辑语言说明以下两个命题为假:
①任何集合都不是空集的子集;②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52ddfcb6c5c9f8b50444386d7221154c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9138d5904f6ff2a48f29e820ce54e0e0.png)
(2)其他教材中有这样一种新命题的表述: 如果把命题“若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/130adfc0b77a1bb4046c19fc52d5fe78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73d277dac920ea0456d486ea528332f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/632244ea6931507f8656e1cc3437d392.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/127a0d8c1c7d15ed40ec4b8bca0ebdf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/485a2d99320384a0857b00ce9ab9e990.png)
(3)证明:原命题“若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d1c79d9d4f43ffb42f22c287058b5f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73d277dac920ea0456d486ea528332f0.png)
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2023·全国·模拟预测
解题方法
5 . 设点
在椭圆
内,直线
.
(1)求
与
的交点个数;
(2)设
为
上的动点,直线
与
相交于
两点.给出下列命题:
①存在点
,使得
成等差数列;
②存在点
,使得
成等差数列;
③存在点
,使得
成等比数列;
请从以上三个命题中选择一个,证明该命题为假命题.
注:若选择多个命题分别作答,则按所做的第一个计分.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c993e34db40190e64654a10b0c13c672.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad523e69a1bf925e73a22900b9855df2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d6678a1a5cc14704ecf06a7648ff543.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d4aca03910382accfe738520daf689c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
①存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f23bfdeeaa1efc12f64328e962d395b.png)
②存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8d3db975e7888ac13b4448b874b972d.png)
③存在点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8d3db975e7888ac13b4448b874b972d.png)
请从以上三个命题中选择一个,证明该命题为假命题.
注:若选择多个命题分别作答,则按所做的第一个计分.
您最近一年使用:0次
解题方法
6 . 设
,过
斜率为
的直线与曲线
交于
,
两点(
在第一象限,
在第四象限).
(1)若
为
中点,证明:
;
(2)设点
,若
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e34f42b3be15518c29e3689c9fe6d6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b62769b7177ef4bc952dc1dd51d6b510.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5db192285632d1991b4ee7a003a52205.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
(1)若
![](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/3ffbb4e6b92463a41bd9460dac6b1ca7.png)
(2)设点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c664dcdcf88a834707b415061bed5dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d5592a72ca90eeb5a9267340c61c673.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc329b32ecf0f0532d09a8a21343e8cb.png)
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7 . 数列
对任意
,且
,均存在正整数
,满足
.
(1)求
可能值;
(2)命题p:若
成等差数列,则
,证明p为真,同时写出p逆命题q,并判断命题q是真是假,说明理由:
(3)若
成立,求数列
的通项公式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f093c61867ee4ce75f951d46b9b123.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0704f453b2de48d36911f7db496bbf82.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c703ace0d2c22dd947a19d8afc74eac7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d9f79b02c30f810f7d9c661fa7e44c7.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/daf464629fa321a6ff7401ab79f07083.png)
(2)命题p:若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26b39cb7d4efd2dd15a1f39ac6ef72c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b30bfc8674948c31b09f824402ebada.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3557b9d9ef8529d963d2cd5962add5e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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真题
8 . (1)若四边形
的对角线
将四边形分成面积相等的两个三角形,证明:直线
必平分对角线
;
(2)写出(1)的逆命题,这个逆命题是否正确?为什么?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
(2)写出(1)的逆命题,这个逆命题是否正确?为什么?
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9 . 下列说法错误的是( )
A.使得![]() ![]() |
B.充分条件就是“有之即可,无之未必不行” |
C.必要条件就是“有之未必行,无之必不行” |
D.没有证明的猜想不是命题 |
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10 . 下列关于用反证法证明一个命题的说法中,正确的是( )
A.将结论与条件同时否定,推出矛盾 |
B.肯定条件,否定结论,推出矛盾 |
C.将被否定的结论当条件,经过推理得出的结论只与原题条件矛盾,才是反证法的正确运用 |
D.将被否定的结论当条件,原题的条件不能当条件 |
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