在Matlab中绘制三维图形和水平曲线

Question

我在下面有下面的代码，但我无法测试它，因为我现在没有Matlab和我在一起，恐怕我没有时间自己测试它了当我终于明白了。我试图绘制三种不同类型函数的y轴和x轴（仅限两维）的电平曲线图和三维图。如果有人能指出下面的代码有什么问题，我将不胜感激。

************************************************************** 
**plotting functions -- level curves and 3d graph** 

x_val = linspace(0, 100, 200); 
y_val = linspace(0, 100, 200); 
[x, y] = meshgrid(x_val, y_val); 
z = ln(x).+y.; 
figure 
contour3(y, x, z) 
contour(y, x, z) 


******************************** 

z = (x.^1/2)+y.; 
figure 
contour3(y, x, z) 
contour(y, x, z) 

********************************* 


z = (x.^1/3)+y.; 
figure 
contour3(y, x, z) 
contour(y, x, z) 

Answer 1

ln不是一个有效的matlab符号，除了上面提到的过多的点和注释格式之外。下面的Matlab运行。

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
%%plotting functions -- level curves and 3d graph%% 

x_val = linspace(0, 100, 200); 
y_val = linspace(0, 100, 200); 
[x, y] = meshgrid(x_val, y_val); 
z = log(x)+y; 
figure 
contour3(y, x, z) 
figure 
contour(y, x, z) 


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 

z = (x.^1/2)+y; 
figure 
contour3(y, x, z) 
figure 
contour(y, x, z) 

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 


z = (x^1/3)+y; 
figure 
contour3(y, x, z) 
figure 
contour(y, x, z) 

Answer 2

对于初学者来说，MATLAB中的注释是“％”而不是“*”。

我想，你有一些错误，试图做元素明智的操作符。

你三个Z的任务有太多的点：“+”

z = log(x)+y; 
z = (x.^1/2)+y; 
z = (x.^1/3)+y; 

这是没有必要使用，因为MATLAB自动将矩阵按元素。