高中数学试验教材第一册 (上 )P1 3 2 的例 4为 :已知Sn 是等比数列 {an}的前n项和 ,S3 ,S9,S6成等差数列 ,求证a2 ,a8,a5成等差数列 .笔者在教学时遵循学生的思维规律 ,采用教材提供的解题思想方法 ,先是师生共同分析解题思路 ,然后让学生自己作答 .除了少部分学生需要指导外 Example 4 of the mathematics experiment textbook for senior high school (top) P1 3 2 is: Known as Sn is the first n terms of the {an} series, and S3, S9, and S6 are the equal arithmetic series to verify that a2, a8, and a5. As a series of arithmetical errors, the author follows the student’s thinking laws in teaching and adopts the problem-solving thinking method provided in the teaching materials. Firstly, the teachers and students jointly analyze the problem-solving ideas, and then let the students answer themselves. Apart from a small number of students who need guidance