i trying to 3d plot, but mesh nor plot3 worked

the function is f(x,y)= 10*x^2*y -5*x^2- 4y^2 -x^4 -2y^4

so when i add "." to the y behind x^2, matlab didn't like it one bit. No matter what i tried it seems to only show a meshgrid plain at best

pic is what i expects it to looks like. And most matlab examples aren't steep like this, so im getting out of ideas too

Answer 1

[the cyclist]

This is what I get from your equation:

xv = -5 : 0.01 : 5;
yv = -5 : 0.01 : 5;

[x,y] = meshgrid(xv,yv);

f = 10*x.^2.*y - 5*x.^2 - 4*y.^2 - x.^4 - 2*y.^4;

figure
mesh(x,y,f)

Are you absolutely sure you keyed the same equation into the two different software systems? (I can't see the full equation in your image.)

[cunny vanilla]

yep, im sure. And i did almost the same code like you, got the same graph too, strangely the web draws it differenly. here is mine code and pic

[x,y] = meshgrid(-10:0.5:10);

z = 10*x.^2*y - 5*x.^2 - 4*y.^2 - x.^4 - 2*y.^4;

mesh(z)

[the cyclist]

Your formula is not the same as mine. You have

10*x.^2*y

instead of

10*x.^2.*y

That's a matrix multiplication instead of an element-by-element multiplication. That's what's causing the difference, not the web vs. local computing.

[cunny vanilla]

ok, now i see it. Thanks for the help