题目

函数y=2sin(x+)-sin(x+4π9)的对称轴方程是__________;对称中心的坐标是__________. 答案：解析：y=2sin(x+)-sin(x++)=2sin(x+)-［sin(x+)+ cos(x+)］=［sin(x+)-12cos(x+)］=sin(x-).对称轴为x-=kπ+(k∈Z),x=kπ+(k∈Z),x-=kπ(k∈Z),x=kπ+,∴对称中心的坐标为(kπ+,0).答案：x=kπ+(k∈Z)  (kπ+,0)(k∈Z).MOSCOW, Oct. 28 (Xinhua) -- Russia's preparations for the FIFA World Cup 2018 have been going ahead of the , FIFA president Sepp Blatter said Tuesday.A. schedule B. transportC. event D. Outline