我弱.想了半天.还跟同学讨论.于是有同学百度了一下.就搜到答案了.其实,你应该百度先以下再问.已经有答案了.平方用“方”代替 =大于等于等价于证2√x+2√y+2√z>=2xy+2yz+2zx.x(3-x)+y(3-y)+z(3-z)3(x+y+z)-x方-y方-z...