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高中数学中有许多题目,求解的思路不难,但解题时,对一些条件的注意,对某些特殊情形的讨论,却很容易被忽略。尤其是在转化过程中,没有注意转化的等价性,会经常出现错误。下面通过对抛物线中常见的例子,剖析致错原因,希望能对同学们的解题有所帮助。一、对抛物线的概念和标准方程理解不熟练【示例1】(1)已知一条曲线上面的每一点到点A(0,2)的距离减去它到x轴的距离的差都是2,则这个曲线的方程是。
There are many problems in high school mathematics, and the solution is not difficult. However, when solving problems, the attention paid to certain conditions and discussions on certain special situations can easily be overlooked. Especially in the conversion process, without paying attention to the equivalence of conversion, mistakes often occur. The following parabola through common examples, analysis of the cause of the error, hoping to help students solve problems. First, the parabolic concepts and standard equations are not well understood [Example 1] (1) It is known that the distance from each point on a curve to point A (0,2) minus the distance to the x axis is 2 , Then the equation of this curve is.