1 . (1)已知
,
.求证:
;
(2)在
中,内角
的对边分别为
.若
,用反证法证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6455e38ff53ede2508e4d9cb23f0b86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91a871ef7bf13de3e15489d65b57a3cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b32e1a1c8cb8f9fdab1d90cb9507c97.png)
(2)在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/432d77fe5ad3032d59a237dd94c8a638.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b774018122dfbf609f08bdbe111e2ab4.png)
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解题方法
2 . 设数列
的前
项和为
,且
,
.
(1)求证:数列
为等比数列;
(2)设数列
的前
项和为
,求证:
为定值;
(3)判断数列
中是否存在三项成等差数列,并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.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/c8370a173854471a3eb27637993a3d5d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea4ac187cbb465180e89f38250b3970.png)
(1)求证:数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)设数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c806dc9bf2cad0cb20220d23bd252a2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1ae9a3b0b7aeb1545b65d91aa371b3c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b87635913b4f90a784edd6ef79f2aec.png)
(3)判断数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf6421b801b00bceab7547d9ed86874e.png)
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名校
解题方法
3 . (1)已知
,求证:
;
(2)若x,y都是正实数,且
,用反证法证明:
与
中至少有一个成立.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ada798eeba5bd19d497bfd0741afd00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbc2278547879e9246de7e749a774d7.png)
(2)若x,y都是正实数,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f9e131cdd242d56b6dba05ab3363ef3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e36ffaf917dcebc8719f2ca539a774ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef8e5b510c343f9d3d626fa1a4b36bad.png)
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2020-06-16更新
|
394次组卷
|
4卷引用:河南省洛阳市2019-2020学年高二下学期期中考试数学 (文)试题
4 . 用合适的方法证明:
(1)已知
,
都是正数,求证:
.
(2)已知
是整数,
是偶数,求证:
也是偶数.
(1)已知
![](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/5a661380bb3fe19bc3c46a4eb16934a0.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8cc0b4997cae4d8aec791a1d3923314.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
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5 . (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
解题方法
6 . 用分析法,综合法或反证法证明:
(1)求证:
;
(2)设
均为正实数,反证法证明:
至少有一个不小于2.
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/add637eef4cd8802b4eb211aa4f6e572.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7810769e3cc469eee1f71f60d36fef25.png)
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7 . 已知函数
.
(1)计算
、
、
的值;
(2)结合(1)的结果,试从中归纳出函数
的一般结论,并证明这个结论;
(3)若实数
满足
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/371fd43a6165652e072311e83f31d100.png)
(1)计算
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eceb5fcaac53060c74822f4fd0554f3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2f9288aa38b66e475764a5e1bfd382c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/614eedae3279fc91b9c9001a8601c650.png)
(2)结合(1)的结果,试从中归纳出函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
(3)若实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79b752f0f189e5d8666daea73e145dff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/374054f44b9a52668f91ac7601e63c06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66f66a2b3d90f0d935d6c8ebaf675349.png)
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8 . 不等式证明:
(1)证明不等式:
(其中
皆为正数)
(2)已知
,
,
,求证:
至少有一个小于2.
(1)证明不等式:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75fbd934eef4b3b38cb981b60cc0af6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b0fffbec1fe851795dfdd448bf0d165.png)
(2)已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67ca5fd57c2c2fcc3c7a574fdd1467d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69bbd0aae5a4f6129fc78f88f662f092.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f3b7d1702786875b9984fe517fa1360.png)
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2020-03-19更新
|
834次组卷
|
3卷引用:陕西省西安中学2017-2018学年高二(实验班)下学期期中数学(理)试题
陕西省西安中学2017-2018学年高二(实验班)下学期期中数学(理)试题河南省南阳华龙高级中学2019-2020学年高二5月月考数学(文)试题(已下线)2.2.2 间接证明-2020-2021学年高二数学(理)课时同步练(人教A版选修2-2)
9 . 对于问题:“已知
是互不相同的正数,求证:三个数
至少有一个数大于2”,用反证法证明上述问题时,要做到的假设是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a14c388e1e2e5a2ff1ccf6caffbee0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/811cdd748e6970fe9d43de8a7597f513.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
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