f'(x)=1-2sinx=0x=π/6,x=5π/6则0<x<π/6,5π/6<x<2π,f'(x)>0,递增π/6<x<5π/6.f'(x)<0,递减所以x=π/6极大,在和边界比较f(π/6)=π/6+√3f(2π)=2π+2显然f(2π)更大所以最大值 是2π+2