Plotting contours of a function

Dear expert.

I am just a beginner when it comes to using MATLAB. Would anybody be so kind and show me the rope of this particular problem? I would like to use this as the base for my further practice.

Let z = f(x, y) = 2x y − y 2 − 4x 2 + 3y.

Draw the contour plot of the function. Point out the local extreme and the saddle point on that figure.

I would like to express my gratitude to your concern!

[madhan ravi]

You need to show some effort. And by posting this question , you should be aware that your professor/teacher could find this thread easily as you do. So after the answerers spend time to answer your question don’t edit your question away by saying some lame reasons.

[Kyle Dalminton]

I appreciate your advice and I am sorry if the way I posted my question gave you the wrong idea. I fully understood and would willingly accept any concequence when I decided to post this question. And also, disregarding the answerers' efforts by editing the question is something that I could never bring myself to do. If you do not have any trust in me, can you suggest anyway that I can do to earn it?

I was not informed about how to use MATLAB and my professor told me to learn from someone other than him. I tried Google but the results were too general. So my last resort was to ask somebody for an advice. I do not need a fully coded answer, all I asked was just a list of things I need to pay attention on. That is what called "the rope" I believe.

Finally, I am very sorry and hope you will forgive me for wasting your time and concern on such an ignorant person who had never touched MATLAB in his life.

I wish you a good day.

[madhan ravi]

Didn’t mean it personally, it was meant generally. Have a good day ;). Don’t be sorry because you didn’t do anything wrong.

[Kyle Dalminton]

Okay, sorry if I went overboard up there :). Your advice has been noted. Thanks again :)

Answer 1

[KSSV]

1. Fix the limits of x and y. Use linspace for this. Read about linspace.
2. Make x, Y to a grid using meshgrid. Read about this.
3. Write your formula i.e f(x,y) interms of matrices X, Y. Read about element by element operations.
4. Now you got f as a matrix, now you can use contourf.
5. To find the local extreme use min. Read about this function.

Read about MATLAB basics. https://www.tutorialspoint.com/matlab/index.htm

[Kyle Dalminton]

Much appreciated my good sir. I had been completely lost until I saw your answer. I will try to figure out the rest on my on.

I wish you a good day.