论文部分内容阅读
在全日制十年制统编数学课本中,常遇到数学推理中一个重要的概念——充分必要条件,使学生清楚地理解这一重要概念,是十分必要的。
In the mathematics textbook of a full-time, ten-year system, one of the important concepts in mathematic reasoning is often encountered—the necessary and sufficient conditions. It is necessary for students to understand this important concept clearly.