1 . 在
中,点
在线段
上,
,
.给出下列三组条件:①
,
的长度;②
,
的长度;③
,
的长度.其中能使
唯一确定的条件的序号为__________ .(写出所有符合要求的条件的序号)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d65639672f444b3d4dc6fc4f357ddbd5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a87afb3e8a6be3a65f65292de018dc05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d97dc3b752832906de41447bb58a341.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
名校
解题方法
2 . 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
解题方法
3 . 对于
ABC,有如下命题:
①若sin2A=sin2B,则
ABC为等腰三角形;
②若sinA=cosB,则
ABC为直角三角形;
③若sin2A+sin2B+cos2C<1,则
ABC为钝角三角形;
④若满足C=
,c=4,a=x的三角形有两个,则实数x的取值范围为(4,8).
其中正确说法的序号是_____ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
①若sin2A=sin2B,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
②若sinA=cosB,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
③若sin2A+sin2B+cos2C<1,则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4cba95fc7d4853a243f8e3fb20ce70.png)
④若满足C=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c67d01e61dc0042e67b5e8ec8e727c22.png)
其中正确说法的序号是
您最近一年使用:0次