同一性是指矛盾双方互相联系、互相依赖、互相贯通的性质,同一性的表现形式之一是矛盾的双方各向自己的对方转化,矛盾双方的这种属性,在解题中有化繁为简、化难为易、优化解题途径的作用,现举数例以示说明.一、常量与变量的同一在不同的变化过程中,常量和变量是相对的而不是绝对的,可根据题意适当转换. Identity refers to the nature of mutuality, interdependence, and interpenetration of two parties to a contradiction. One of the manifestations of identity is the transformation of the contradictory parties into their own counterparts. This attribute of contradictory parties has a tendency to multiply in solving problems. Simple, difficult, and easy to solve, to optimize the role of the solution to the problem, now give a few examples to illustrate. First, constants and variables in the same process in different changes, constants and variables are relative rather than absolute, according to the meaning of Appropriate conversion.