初中三年级数学课本第五册,P25、P183的习题中各提到定值问题,可见这类问题要求学生了解,至少是要求学习基础较好的同学了解。定值问题较一般问题,思考起来需要深入一步。解这类问题有利于巩固基础知识,发展思维能力,调动学生的学习积极性。定值问题一般都有运动的概念,可以培养学生运动、变化的观点,启发提高学生的学习能力。所以对定值问题,应该向学生讲解清楚。 平面几何中的定值问题,对初中学生来说难于入 In the third grade mathematics textbook for junior high school fifth grade, P25 and P183 mentioned the fixed value problem in each exercise. It can be seen that this kind of problem requires students to understand, at least, the students who require a good foundation of learning to understand. The fixed value problem needs a further step to be taken into consideration than the general problem. Solving this type of problem is conducive to consolidating basic knowledge, developing thinking skills, and mobilizing students’ enthusiasm for learning. Fixed value problems generally have the concept of sports, which can cultivate students’ movements, change their views, and inspire students to improve their learning ability. Therefore, for the fixed value problem, it should be explained clearly to the students. Fixed value problem in plane geometry is difficult for junior high school students