这是我不久前听的数学课

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椭圆b.线段c。老师指导学生根据椭圆的定义来分析这个问题,显然,问题情况有两个固定点,从移动点到两个固定点的距离之和是恒定的,似乎完全符合椭圆的定义。经过这样的操作和讨论,老师和学生得出以下结论:对于两个固定点f1和f2,如果从移动点到两个固定点的距离之和为常数,有三个结果:

当常数> | f1f2 |时,轨道是椭圆形的。

在.的基础上,老师要求学生再做一份工作,给图钉和固定长度的细线,要求学生遵循问题的要求,确定纸板上两个固定点的位置,然后选择一条符合要求的细线,实际去做吧可以看到的痕迹是什么。oh.do not,it should be 2a=|f1f2|.

teacher: what about answer c?

student: |f1f2|=0

teacher: what if answer d is true?

student: 2a<|F1F2|.

  Two, some thoughts

  1.Pay attention to concept teaching

  Recently, when communicating with some mathematics experts,It is generally felt that teachers do not pay enough attention to the teaching of mathematical concepts in the classroom.Many teachers are explaining the "ellipse and its standard equation" in this class,Not much time is spent on understanding the concept of ellipse.Teachers may have a judgment,I think the definition of ellipse is very clear in the textbook,White and black,Just read the book to understand,There is no need to talk more.So after simply deriving the definition of the ellipse,Immediately focus on the study of the elliptic standard equation.

  in fact,The text written on the book,Can students really understand,It's going to be a big question mark.The above case tells us,Students read the definition of ellipse,I didn't really understand this concept,Otherwise, when dealing with the problem given by the teacher,The answers are varied.The teacher spent more than ten minutes,Students can understand the three elements of the ellipse concept-in the same plane; two fixed points F1, F2; 2a>|f1f2|.

。 教学总结

老师在教学之初,向学生展示了神舟七号的“ c娥奔月”相关图片,导致椭圆的概念,并让学生列举日常生活中的椭圆。没有曲目

学生分析这个问题,但是他们似乎有不同的理解,有椭圆形的选择线路后,没有曲目选项。 今天的博客文章借助“椭圆”概念教学,对“知觉-体验-体验”学习过程的解释。圈子d。这是我不久前听的数学课,我是数学教学的外行,但我同意老师在椭圆概念上所做的努力,这是我个人的一些看法,不当,在要求大家批评和纠正我之后。

师:知道椭圆的定义,我们可以用它来判断运动点的轨迹是否为椭圆形吗?请确定以下问题的答案:

给定两个固定点f1和f2和| f1f2 | = 4,那么到f1和f2的距离之和为4的点m的轨迹是:

一种。

当常数= | f1f2 |时,轨迹是线段f1f2;

当常数 <|F1F2|,No track.

  After this discussion,The students seem to have understood the definition of ellipse,But the teacher is still worried,Ask a student to write the geometric equation of the ellipse on the blackboard.

  Student: |MF1|+|MF2|=2a

  The student wrote this equation and returned to his seat.Another student found the problem,Point out that there is a restriction: 2a>|F1F2|,Otherwise, the three possibilities mentioned above will be discussed.This student's correction,It resonated with everyone.

  Hello teacher,According to the geometric equation of the ellipse,|MF1|+|MF2|=2a (2a>| f1f2 |),让我们再看一下上面的例子,为了使答案b为真,对上述方程式及其约束条件应作哪些调整?

学生:2a<| F1F2 |。

  师:椭圆形很漂亮,在生活中被广泛使用从上面, 我们可以看到它在生活中的体现和应用, 建筑, 天文学, 等等因此, 我们有必要研究椭圆。 等等对于特定对象,老师特别强调“横断面”,将椭圆的研究限制在一个平面上。学生想了很多如大地 地球的轨道 蛋, 橄榄球 油船。

  1。老师要求学生进一步研究这个概念,学生们还发现有一个要求“常量> | f1f2 |” 在椭圆的定义中。那么椭圆是什么条件呢?

老师指导学生读书,在课本中找出椭圆的定义

(作者:佚名 编辑:admin)

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