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关于动点对定线段所张的角为定值问题,从表面上看似与圆无关,但如果我们能深入挖掘题目中的隐含条件,善于联想所学定理,巧妙地构造符合题意特征的辅助圆,再利用圆的有关性质来解决问题,往往能起到化隐为显、化难为易的解题效果.本文以部分中考试题为例,说明这类问题的构造策略.问题1(2014年陕西中考题)(1)如图1,在矩形ABCD中,AB=3,BC=4,如果BC
On the fixed point of the fixed point angle fixed value problem, the surface seems to have nothing to do with the circle, but if we can dig deeper in the subject of implicit conditions, good at associative theory, subtly constructed in line with the characteristics of the question Of the auxiliary circle, and then use the circle of the nature to solve the problem, often can play a hidden latent, difficult to solve the problem easily.This paper takes part of the senior high school entrance examination questions as an example, to illustrate the construction strategy of such problems.Question 1 ( 2014 Shaanxi test questions) (1) Figure 1, in the rectangular ABCD, AB = 3, BC = 4, if BC