名校
解题方法
1 . 对下列命题:
(1)
的最小值为4;
(2)若
是各项均为正数的等比数列,则
是等差数列;
(3)已知
的三个内角
所对的边分别为
,
,
,且最大边长为
,若
,则
一定是锐角三角形;
其中所有正确命题的序号为_________ (填出所有正确命题的序号).
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24539bf655f0693621fdf36098346de2.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dc71a2fd8c6b263feea5ff5d6a36121.png)
(3)已知
![](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/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/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95563a79e3b68c597ae1e5167516ff88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
其中所有正确命题的序号为
您最近一年使用:0次
名校
解题方法
2 . 给出下列四个命题:
①若
,则
为等腰三角形;
②函数
的最大值为
;
③在
中,若
,则
的形状是钝角三角形;
④用篱笆围一个面积为
的矩形菜园,要使所用篱笆周长最短,则所用篱笆最短的周长是
.
其中正确的序号为__________ (注:把你认为正确的序号都填上)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b883d9703a1deaf8dbc18097c6b8bb2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
②函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/89deb3ed56b145b87f4711a49b8ab094.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
③在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/272058608afabdb02a59321e1bffe344.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
④用篱笆围一个面积为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6711f79513b534982a9ada2b625e9fdd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45c758c27bec97c234d1d818c40f3d3f.png)
其中正确的序号为
您最近一年使用:0次
名校
解题方法
3 . 给出以下几个结论:
①若等比数列
前n项和为
,
,则实数
;
②若数列
,
的通项公式分别
,
,且
,对任意
恒成立,则实数a的取值范围是
;
③设在
中,内角A、B、C的对边分别为a、b、c,且
,则
的最大值为
;
④在
中,三内角A,B,C所对的边分别为a,b,c,则
;
其中正确结论的序号为______ .
①若等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97b794ed9de8e93de6e067c3d0259558.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145b6046bc80d0ffecc61ac67c87ca1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b108ab31cc093f03cf48ad65429889e.png)
②若数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20ae956b7c89f63fcb27a507c9728344.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dc7eb66f5d777c283a395eda5635d4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83ac679ad239090a6ce21a10b47e332c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e145b6046bc80d0ffecc61ac67c87ca1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54c30f7465c99d88caf6703bc7365a51.png)
③设在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1f32fe2cea6b046da549c0d04e103e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afd0b09f2c1c75840f0a1a1eb3528ae3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/827ccf0c04aa941ba20d5f4c6068b46b.png)
④在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d22b0c674439368ca4d402fe8ce0888.png)
其中正确结论的序号为
您最近一年使用:0次
名校
4 . 给出下列叙述:
①正四面体
的棱长为
,
是棱
的中点,则异面直线
与
所成角的余弦值是
;
②在等比数列
中前
项和为
,前
项和为
,则前
项和为
;
③直线
关于直线
对称的直线方程为
;
④若
,
,且
,则
的最小值为
;
其中所有正确叙述的序号是_____________ .
①正四面体
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3241d7fedd89d85711acd7a2635298af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bdaa19de263700a15fcf213d64a8cd57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69a8b76e36783a69d14ec54af82c7df0.png)
②在等比数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b53c7539ed297ea63b9ace6f5cc58ca8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fad491e5b5e14c49ef8b7004ebcfcef9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ade9841a8e6840efddcfd8620a6fc1fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b88b4213192069c5c22e7c97f6242c11.png)
③直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/056e249d0c33ef92b956f84937fa9324.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35dd2b23130371b570ed71f8a6e23311.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f503de26e16e1a0ab7be45df505e1c2.png)
④若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08115d6d9f876dea921a4d32260ff1fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/061813f1ec633c5c4c393c4de7938322.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/637a04c9fd4fb91fd89e60aca2f86b4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c633cc3cfa5df8130f87f78b32ce38dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc0d80fd60126ee6128f67a8e87a926c.png)
其中所有正确叙述的序号是
您最近一年使用:0次