已知△ABC中,角A、B、C的对边分别为a、b、c,且
, 则
的值是______________ .
![](https://img.xkw.com/dksih/QBM/2015/3/27/1572041501442048/1572041507127296/STEM/3f19abf4a0464390956f1d0b99ac29a0.png?resizew=103)
![](https://img.xkw.com/dksih/QBM/2015/3/27/1572041501442048/1572041507127296/STEM/5353d0df10ac4dc19e4201476d72dea1.png?resizew=27)
更新时间:2016-12-03 11:09:32
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【知识点】 余弦定理边角互化的应用解读
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填空题-单空题
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容易
(0.94)
解题方法
【推荐1】已知
,
为椭圆
(
)的两个焦点,B为椭圆短轴的一个端点,
,则椭圆离心率的取值范围为____________ .
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容易
(0.94)
真题
名校
【推荐2】设
的内角
所对的边为
;则下列命题正确的是_________
①若
;则
②若
;则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6e5604ce8f1fbcdfe9b42b74cdc9e9d.png)
③若
;则
④若
;则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c31b95c668a5bcc8c93479405ca6f0f.png)
⑤若
;则
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6b489ff67a08117de227196cb06fb6a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6e5604ce8f1fbcdfe9b42b74cdc9e9d.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6e5604ce8f1fbcdfe9b42b74cdc9e9d.png)
③若
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b28a2f873db9f7ecbe6f2167f31f7f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05b101ddff0e452d45e49484129e58bb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c31b95c668a5bcc8c93479405ca6f0f.png)
⑤若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66990b850f57a61b5a6c7d3ac67aade0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e060da00ae96adf38f6d1253af02f7e.png)
您最近一年使用:0次