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1 问题背景某校招聘老师,笔者有幸听了一位优秀教师(说课比赛获省第一名,全国二等奖)的试教课,课题是“椭圆的参数方程”.该教师的上课流程大致是:首先向学生提出下列问题:(1)已知圆心(a,6)和半径r,该圆的方程是什么?参数方程又是什么?(2)什么叫做曲线的参数方程?待学生回答后,接着出示问题(教师边叙述边画图):如图1,以原点为圆心,分别以 a、6(a>b>0)为半径作两个圆,点 B 是大圆半径 OA 与小圆的交点,过点 A 作 AN⊥O_x,垂足为 N,过点 B 作 BM
1 Question background A teacher recruiting a school, the author had the privilege of listening to an excellent teacher (said the lesson contest won the first prize in the province, the second prize in the country) of the trial course, the subject is “parametric equation of the ellipse”. The teacher’s class process Yes: First, ask the students the following questions: (1) Knowing the center of the circle (a, 6) and the radius r. What is the equation of the circle? What is the parameter equation? (2) What is the parametric equation of the curve? After that, we present the question (teacher side narrates and draws the picture): As shown in Figure 1, the origin is taken as the center, and a and 6 (a>b>0) are used as the radius to make two circles. Point B is the big circle radius OA and the small circle The point of intersection, crossing point A for AN⊥O_x, foot for N, point B for BM