一次函数似乎无处不在.它活跃在各类试题中,兹举例说明如下.一、一次函数在平面几何图形中例1如图1,平面直角坐标系中,正ΔABC的顶点B,C的坐标分别为B(1,0),C(3,0),过坐标原点O的一条直线MN分别与边AB,AC交于点M,N,若OM=MN,求点M的坐标.分析与思考本题看似简单,但具体做起来却又似乎无从下手.如图1,尝试过点M作MP与AC平行,交 A function seems to be everywhere. It is active in all kinds of questions, are given as an example below. A primary function in the plane geometry Example 1 Figure 1, Cartesian coordinate system, the vertices of the positive ΔABC B, C coordinates Respectively, B (1,0), C (3,0), a straight line through the origin O coordinates MN, respectively, with the edge AB, AC intersection M, N, if OM = MN, find the coordinates of point M. Analysis and Thinking this question may seem simple, but it does not seem possible to start with the concrete.As shown in Figure 1, try to point M for MP and AC parallel, pay