Title: The concept of parabola
Teaching process:
Teacher: We learned the concepts of ellipse and hyperbola in the last few classes. Do the students remember the definitions of these two curves? The students quickly answered the first definition of these two curves. )
Teacher: Can you unify the definitions of these two curves?
Health: The ratio of the distance from a fixed point to a straight line in the plane is constant E. When 0 < e < 1, the trajectory of the point is ellipse, and when e > 1, the trajectory is hyperbola.
Teacher: What will be the trajectory when e= 1 (tell me about it, students)? Today we will learn the trajectory of e = 1- parabola.
Next, the teacher demonstrated with teaching AIDS to get the trajectory diagram, and then used the previously learned method of finding the trajectory to get the parabolic equation. Then students do classroom exercises, the teacher summarizes, emphasizes the problems that should be paid attention to, and assigns homework.
Student feedback record (afternoon self-study class):
Student A: (takes out his exercise book): Teacher, can you help me make up the content of this morning's class?
Teacher: OK! Why don't you tell me which one is unclear first?
Student A: Tell me about this homework problem: If the distance between moving point P and straight line 2x+3y-5=0 and point M( 1, 1) is equal, then the trajectory of point P is () A ellipse B hyperbola C parabola D straight line. Why did I choose C? It's wrong to have a B.
Student B: She didn't attend class at all. She has been in a daze.
Student A: Wrong! I have been listening carefully, and I remember everything the teacher said.
Teacher: You two can exchange learning experiences with each other. For example, if you are a student, you can tell him why A can't choose C!
Student B: I just taught her, but she said she did it according to the definition in the textbook. Why is it wrong to follow the definition? Teacher, actually, I think there seems to be something wrong with this definition. Why doesn't the definition in the textbook say that points can't be in a straight line? I didn't know I chose D until I remembered what you said. When she said she would ask, I thought: I might be more practical if I listen to it again.