f(x)=2[1/2*sin(x+a)+√3/2*cos(x+a)]=2[sin(x+a)cosπ/3+cos(x+a)sinπ/3]=2sin(x+a+π/3)是偶函数f(-x)=f(x)sin(-x+a+π/3)=sin(x+a+π/3)所以-x+a+π/3=2kπ+(x+a+π/3)或-x+a+π/3=2kπ+π-(x+a+π/3)-x+a+π/3=...