A:y=2sin(2x+ 2π3 )
B:y=2sin(2x+ π3 )
C:y=2sin( x2 ﹣ π3 )
D:y=2sin(2x﹣ π3 )
由四个全等的直角三角形如图所示的“赵爽弦图”,若直角三角形斜边长为2,一个锐角为30°,则图中阴影部分的面积为( )
The World Health Organization has given some advice on how to protect us from infected(感染) with H7N9.
根据下图及描述,回答下列问题: