设定义在R上的函数 f ( x )是最小正周期为2π的偶函数; f ′( x )是 f ( x )的导函数,当 x ∈[0,π]时,0< f ( x )<1;当 x ∈(0,π)且 x ≠ 时, f ′( x )>0.则函数 y = f ( x )-sin x 在[-2π,2π]上的零点个数为________.
【简答题】Thanksgiving is an important festival in North America. We interviewed several students from the US and Canada. Here is what they have told us about their Thanksgiving experiences. Josie from New York...