二次函数是初中数学中的重要内容,一些函数问题运用对称性进行解答显得方便快捷,现举例说明其应用,以帮助大家熟练掌握方法,最终形成解题策略。1.运用对称性求代数式的值例1(2014·扬州)如图,抛物线y=ax~2+bx+c(a>0)的对称轴是过点(1,0)且平行于y轴的直线,若点P(4,0)在该抛物 The quadratic function is an important part of the junior high school mathematics. It is convenient and quick to solve some function problems by using the symmetry. Now the application of the function is illustrated to help you master the methods and finally form a solution strategy. 1. Use symmetry to find algebraic expressions. Example 1 (2014, Yangzhou) As shown in the figure, the symmetry axis of the parabola y=ax~2+bx+c(a>0) is the crossing point (1,0) and is parallel to the y axis. The straight line, if point P(4,0) in the parabola