(1)计算:![](https://img.xkw.com/dksih/QBM/2014/9/26/1573750580740096/1573750586073088/STEM/b0ca9d678cd845b7a776864816f9c62e.png)
(2)先化简,再求值:
![](https://img.xkw.com/dksih/QBM/2014/9/26/1573750580740096/1573750586073088/STEM/b0ca9d678cd845b7a776864816f9c62e.png)
(2)先化简,再求值:
![](https://img.xkw.com/dksih/QBM/2014/9/26/1573750580740096/1573750586073088/STEM/58b3deaa3c48471dbc1ca4364d007f33.png)
更新时间:2016-12-05 21:06:40
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【知识点】 特殊角的三角函数值