如图,在Rt△ABC中,∠C=90°,AC=1,BC=2,则cosB的值是( )
![](https://img.xkw.com/dksih/QBM/2015/2/10/1573799214219264/1573799220264960/STEM/402add803a49490b82fe8a7ab5142b61.png)
![](https://img.xkw.com/dksih/QBM/2015/2/10/1573799214219264/1573799220264960/STEM/402add803a49490b82fe8a7ab5142b61.png)
A.![]() | B.![]() | C.![]() | D.2 |
更新时间:2015-02-10 08:52:50
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【知识点】 勾股定理及逆定理
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