由于存在型问题具有开放性的特点,能够十分有效地考查学生的数学素质,因而成为竞赛、高考和其它各类考试命题的热点.本文仅就数列中存在型问题的求解策略作些归纳,以期对大家的学习有所启发和帮助.一、直接探究例1已知Sn是数列{an}的前n项和,且Sn=2an-3n.问:数列{an}中是否存在 Due to the openness of existential problems, students’ mathematics diathesis can be examined very effectively. Therefore, it becomes a hot spot for competitions, college entrance examinations and other examination propositions. This article only summarizes the strategies for solving existential problems in series. Inspired and helpful to everyone’s learning. 1. Directly exploring example 1. Known Sn is the first n sum of the series {an}, and Sn = 2an-3n. Q: Is there a sequence of {an}