plot - 2-D line plot

    This MATLAB function creates a 2-D line plot of the data in Y versus the
    corresponding values in X.If X and Y are both vectors, then they must have equal
    length and MATLAB plots Y versus X.If X and Y are both matrices, then they must
    have equal size and MATLAB plots columns of Y versus columns of X.If one of X or
    Y is a vector and the other is a matrix, then the matrix must have dimensions
    such that one of its dimensions equals the vector length.

    plot(X,Y)
    plot(X,Y,LineSpec)
    plot(X1,Y1,...,Xn,Yn)
    plot(X1,Y1,LineSpec1,...,Xn,Yn,LineSpecn)
    plot(Y)
    plot(Y,LineSpec)
    plot(___,Name,Value)
    plot(axes_handle,___)
    h = plot(___)
注释：
对于X和Y,可以有以下几种参数形式
(1)X是向量（行向量或列向量），Y是向量（行向量或列向量），并且length(x)==length(y)。
(2)X,Y是M*N的矩阵，Y中的每一列元素为纵坐标，绘制N条曲线。第一条曲线我的坐标为：[x11,y11],[x12,y12],..[x1M,y1M]
(3)X是向量，Y是函数。绘制出Y=F(X)的函数图。
举例1：
x=[1,3,5,6]
y=[0.1,0.2,0.3,0.4]
plot(x,y)
举例2：
x=[1,5,9;2,4,8]
y=x
plot(x,y)
%绘制出三段曲线
第一段曲线：(1,1),(2,2)
第二段曲线：(5,5),(4,4)
第三段曲线：(8,8),(9,9)

举例3：

x=[0:pi/10:2*pi]  %[0,2*pi]间隔为pi/10的向量
y-sin(x)
plot(x,y)