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如图,直径为10的⊙A经过点C(0,5)和点O(0,0),B是y轴右侧⊙A优弧上...
如图,直径为10的⊙A经过点C(0,5)和点O(0,0),B是y轴右侧⊙A优弧上一点,则∠OBC的正弦值为( )
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131101192737362094545/SYS201311011927373620945013_ST/images0.png)
A.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131101192737362094545/SYS201311011927373620945013_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131101192737362094545/SYS201311011927373620945013_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131101192737362094545/SYS201311011927373620945013_ST/2.png)
D.
![manfen5.com 满分网](http://img.manfen5.com/res/CZSX/web/STSource/20131101192737362094545/SYS201311011927373620945013_ST/3.png)
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