“生活即数学”.本文以二次函数为例,谈谈二次函数在现实生活中的应用.一、桥梁问题例1有一座抛物线型拱桥,桥下面在正常水位时AB宽为20米,水位上升3米就达到警戒线CD,这时水面宽为10米.(1)在如图1的坐标系中求抛物线的解析式; “Life is mathematics”. This article uses the quadratic function as an example to talk about the application of quadratic function in real life. First, bridge problem Example 1 There is a parabolic arch bridge. Under the bridge, at the normal water level, AB width is 20 meters. When the water level rises by 3 meters, it reaches the warning line CD. At this time, the width of the water surface is 10 meters. (1) In the coordinate system shown in Fig. 1, the analytical expression of the parabola is obtained;