解题方法
1 . 已知
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ceb912396f8c73913e16a3349f5c2a56.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f089e940a29dfb93d7a649fdd5905a0.png)
A.![]() | B.![]() | C.![]() | D.![]() |
您最近一年使用:0次
2 . 在
中,内角A,B,C所对的边分别是
,已知8b=5c,C=2B,则cosC=
![](https://img.xkw.com/dksih/QBM/2012/7/6/1570917326241792/1570917331304448/STEM/a4970ee58c2b42508e9bbc915d097bef.png)
![](https://img.xkw.com/dksih/QBM/2012/7/6/1570917326241792/1570917331304448/STEM/685f44fd40124b4f89de554d372d8853.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
您最近一年使用:0次