a＞b,则a-b＞0,则：（a²+b²)/(a-b)=[a²+b²-2ab+2ab]/(a-b)=[(a-b)²+2ab]/(a-b)=(a-b)+2/(a-b) 这里把ab=1代入了.且(a-b)＞0,2/(a-b) ＞0≥2√[（a-b)*2/(a-b)]=2√2,此时(a-b)²=2,存...