数列和式不等式的证明经常在竞赛题或试卷压轴题的最后一问出现,在思维能力和方法上要求很高,往往让人束手无策.其实,这类不等式的证明,是有章可循的.遵循什么章?就是要把和求出来,求出后再放缩.更多的情况下是不能直接求和的,这时就要先把通项放大或缩小,使得每一项按照相同的 Proof of series and inequality often appears in the last question of the competition questions or test questions, which are very demanding in terms of thinking ability and method, often making people lose their hands. In fact, the proof of such inequalities is rule-based. What chapter to follow? It is to be summed to find and then zoom out. In more cases can not be directly summed up, then we must first enlarge or narrow the pass, so that each in accordance with the same