设y=sin^(x/2)-(x/2)^2y'=0.5(sinx-x)画出y1=sinx和y2=x的图像两直线在(0,0)的斜率为k(y1)=1,k(y2)=1且两直线在x=π/2处,有y1=1,y2= π/2 故y1的图像始终在y2的下面,即在(x>0)y'=0.5(sinx-x)0))同理可得sin^(x/2)≥(...