a2\b+b2\c+c2\a+(a+b+c)=(a2\b+b)+(b2\c+c)+(c2\a+a)=(a2+b2)\b+(b2+c2)\c+(c2+a2)\a因为a,b,c为正实数,(a-b)2>=0 --> a2+b2>=2ab同理: b2+c2>=2bc c2+a2>=2ac则:原式=(a2+b2)\b+(b2+c2)\c+(c2+a2)\a>=2ab\b+2bc\c...