近几年来,曾一度降温的由递推关系式求通项的数列问题又悄然升温,而学生对此类题型不知所措,缺乏化归能力.究其原因,与教师在教学中对知识的形成重视不够有关.其实,正向知识变迁是逆向化归的基础,在数列复习中,笔者从一个简单的例子出发,进行演变、派生,再现复杂的递推关系式, In recent years, the once-describable series of problem-solving relations have quietly warmed up, and students are overwhelmed with such questions and lack the ability to convert. The reason is that the teachers have knowledge in teaching. The formation of attention is not enough. In fact, the positive knowledge change is the basis of reverse transformation. In the series review, the author proceeds from a simple example, evolves, derives, reproduces a complex recursive relation,