数列是中学数学的重要内容,也是高考命题的热点.在解题时,解题方法是否得当,常常导致解题的难易、繁简的差异.因 The series is an important content of middle school mathematics, and it is also a hot spot of college entrance examination propositions. When solving a problem, whether the problem-solving method is appropriate or not often leads to the difficulty in solving the problem and the differences in the complexity.