您正在关注此问题

您将在关注的内容源中看到更新。
您可能会收到电子邮件，具体取决于您的通信预设项。

How to complete this matrix?

2 次查看（过去 30 天）

显示更早的评论

Briana Pass 2019-10-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix

⋮

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix

评论： Briana Pass 2019-10-23

Use the meshgrid function with the following data: -8: 0.5: 8
Use the following equation: R=x2+y2 treat x and y as vectors
Use the Z=sin RR
Hint: you will need the following: Z(R==0)=1
Use the mesh function for you variables

10 个评论
显示 8更早的评论隐藏 8更早的评论

Rik 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759298

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759298

This is your homework. What have you tried so far?

Briana Pass 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759392

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759392

在 MATLAB Online 中打开

x=-8:0.5:8;
[x,y] = meshgrid (x);
R=sqrt(x.^2+y.^2)
surf(x,y,R)

Guillaume 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759398

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759398

Reusing the same variable name (x) for two different purpose is not a good idea. There's no limitation to the number of variables you can have.

You seem to have done step 1) and 2) and skipped 3) and 4). What's preventing you from doing these (other than them being very unclear as you've written them)?

Briana Pass 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759403

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759403

In which line should I change X? Whenever I code lines 3 and 4 I reinforce error. This is how I coded it. Z= sin®/R Z=(R==0)=1 How do I fix this ?

Cyrus Tirband 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759440

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759440

What is the error you get? Can you format your code using the code blocks in the comments? It looks like you have the right answer, but it's hard to tell because of the awful typesetting. Are you using the pointwise division operator (./) to calculate Z?

Guillaume 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759443

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759443

In which line should I change X

Whichever you want, but it makes more sense to keep the output of meshgrid as x, since that's what your assignment use. The first x which serves a completely different purpose could be renamed to gridspacing or something similar.

Briana Pass 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759444

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759444

I included the image I got too. I know it is not right. I do not know where I am making the error.

x=-8:0.5:8;

Y=-8:0:8;

Z=-8:1.5:8;

[x,Y] = meshgrid (-8:0.5:8);

R=sqrt(exp(-x.^2-Y.^2))

surf(x,Y,x.*exp(R))

Z(R==0)=1

Screen Shot 2019-10-23 at 9.36.31 AM.png

Cyrus Tirband 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759448

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759448

The assignment is asking you to plot z = sin (R)/R, you're plotting x*exp(R).

If you define Z like was asked, you'll have to account for the location where R = 0 (given the snippet you were given) because matlab will naïvely divide zero by zero and give you NaN or Inf. You can then plot Z with the surf command. You'll get something like this

Guillaume 2019-10-23

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759461

⋮

链接

此评论的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/486914-how-to-complete-this-matrix#comment_759461

matlab will naïvely divide zero by zero and give you NaN or Inf

There is nothing naive about it. dividing zero by zero is mathematically undefined. Matlab will give you NaN (not a number) if you still do it, never Inf for that.

The function