中文说明：利用MATLAB进行定义分段函数的定义，并绘制其曲线函数定义成 MATLAB function ，求解两个分段函数在给定区间内的给定任意x值时对应的y值。利用MATLAB求解过程较为快捷方便，而且画成图形也能够体现出分段函数的特性。
English Description：
Matlab is used to define the piecewise function and draw its curve. The function is defined as MATLAB function to solve the y value of two piecewise functions in a given interval when x value is given. Using MATLAB to solve the problem is fast and convenient, and drawing a graph can also reflect the characteristics of piecewise function.