1 . 将数列
和
的公共项从小到大排列得到数列
,记
的前
项和为
.
(1)求
的通项公式;
(2)求使得
的
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b3b236ce5ac46bf29625249180af284.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33a023e8c7e533834a3a00f6113eea60.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](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/6a3f1f8813adcedd56b471961b2ad6a6.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(2)求使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ade47598510917b18557339027024b69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
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2 . 记
的内角A,B,C的对边分别为a,b,c,已知
.
(1)求A;
(2)若
,角A的平分线交BC于点D,求AD;
(3)若
的面积为
,求a的最小值;
(4)若BC边上的中线长为
,且
的外接圆半径为
,求
的周长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b11d83cc4abd3886788064b177a46c4.png)
(1)求A;
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59dd9cc29b4246a34c2d3700c97bd664.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/802e162b98c280720fcb909cf392fda3.png)
(4)若BC边上的中线长为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/533a7b702ada1dd80123e4041271d521.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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3 . 如图,一艘货轮从码头O出发沿北偏东30°的OD方向以20海里/小时的速度驶往目的地,出发后发现燃料不足,立即联系位于O正东方向120海里的A处的加油船在中途加油补充燃料,假设加油船与货轮同时出发,但加油船要先到小岛B处补给物资再赶往货轮处,已知小岛B在码头O北偏东60°方向,也在A北偏西30°方向上,加油船在B处补给物资需要1个小时,且加油船航行速度始终为60海里/小时.
(2)两艘船最少经过多少小时能相遇?
(2)两艘船最少经过多少小时能相遇?
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解题方法
4 . 已知
中,角A,B,C的对边分别为a,b,c,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7112e7ccb1eb90facfa5182ea763970a.png)
______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c9da42515f4cc2fdeb7e332156f0cd5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7112e7ccb1eb90facfa5182ea763970a.png)
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解题方法
5 . 已知非零向量
,
满足
,则( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a2f4b1178f68bd147d1a2a6acd04435.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c94075193c11fe43f2396cff5a485054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc22084cd0c860f3046c9cbb11443d09.png)
A.![]() ![]() ![]() |
B.![]() |
C.若![]() ![]() ![]() ![]() |
D.若![]() ![]() ![]() ![]() ![]() |
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6 . 下列命题为真命题的有( )
A.若![]() ![]() |
B.不等式![]() ![]() |
C.已知实数a,b满足![]() ![]() |
D.若关于x的不等式![]() ![]() ![]() |
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解题方法
7 . 在△ABC中,角A,B,C所对的边长分别为
,
,
,
,
且
,
(1)求
的长度;
(2)求
的面积;
![](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/154c0fe2aaaa1f7c3bdde6db950e6583.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e787dd4c34300c3a3642068b05c26d0c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82f5744572e6103f4438758cf0be2a1a.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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8 . 定义
三边长分别为
,
,
,则称三元无序数组
为三角形数.记
为三角形数的全集,即
.
(1)证明:“
”是“
”的充分不必要条件;
(2)若锐角
内接于圆O,且
,设
.
①若
,求
;
②证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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/10a57d1215099fab4a97db12b2fa8f14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c53315b1196d5a34560cc77995f817d.png)
(1)证明:“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c53315b1196d5a34560cc77995f817d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7b83cd3d2de78fbc430205d724b8edf.png)
(2)若锐角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4a9c6bcfb1f63e1e57cccbcfb07e885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3641602ab775f0425debe0ec778c0ba2.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc6dfc6ee5b72469c51c6b5cc44ad72e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0839f7ef584b094ff45fdf01bb8f117e.png)
②证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90dfb13026887496470c48ed52e46fb0.png)
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9 . 相看两不厌,只有敬亭山.李白曾七次登顶拜访的敬亭山位于安徽省宣城市北郊,其上有一座太白独坐楼(如图(1)),如图(2),
中,内角
,
,
的对边分别为
,
,
,
,
,
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4e9bb42376c12d7d21702ae8062b25a.png)
______ ,
的面积=______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.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/8e258ab9e600435b37465092243d99f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcdb7a488910743dc5c63afb394b87e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84d81d732204a3c2384a27606f858677.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4e9bb42376c12d7d21702ae8062b25a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
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10 . 在
中,已知
,
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09947ea5c9ea0fe010027f2aa91138b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7aeb2a8d1437eeb4482c3b6ad9f315.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae248960d8c1677cf948f8251275e863.png)
A.1 | B.![]() | C.![]() | D.![]() |
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