在前面几期我们已经对数学进行了比较系统的复习,但还是有很多同学反映在解题时经常出错,暴露出知识的薄弱点和盲点.“错误是最好的老师.”同学们要认真地纠正错误,最重要的是找出产生错误的原因,及时进行归纳和总结,查漏补缺.本期组织的这四篇文章,希望能够对同学们的复习有所帮助. In the previous periods we have conducted a systematic review of mathematics, but there are still a lot of students who are often mistakes in solving the problem, revealing weaknesses in knowledge and blind spots. “Errors are the best teachers.” Students To seriously correct mistakes, the most important thing is to find out the reasons for the mistakes, and to sum up and sum up in a timely manner to find out what is missing. The four articles organized in this issue hope to help the review of the students.