Problem with ploting exp function

I try to plot t(x,y) = (x^2 - 2y^2)*e^(x-y) in Matlab and i use the following code

t=@(x,y)((x.^2-2*y.^2).*exp(x-y));

x = -1:2/50:1;

y = -2:4/50:2;

[X, Y] = meshgrid(x, y);

surf(X, Y, t(X,Y));

rotate3d on;

I got the result but it is not the same as i drawn in Geogebra

I think there is a problem with .*exp(x-y)

[Alberto Cuadra Lara]

Hello Dinh,

The function looks good. Are you using the same limits in Geogebra?

[Dinh Le Dung]

This is what Matlab gives

This is what Geogebra gives.

They look pretty much not the same :((

[Walter Roberson]

Very different plotting ranges.

[Dinh Le Dung]

I see, thanks for your help sir!

Answer 1

[Stephen23]

"I think there is a problem with .*exp(x-y)"

I doubt that. Did you look at the domains and ranges that you are plotting?

Your Geogebra example shows that you plotted over x = -8..+8 and y = -8..+8. Then in MATLAB you plotted over x = -1..1 and y = -2..2. And then you did not limit the Z axes to the same range as your example plot. Lets try that now:

x = -8:0.5:8;
y = -8:0.5:8;
[X,Y] = meshgrid(x,y);
T = (X.^2-2*Y.^2).*exp(X-Y);
surf(X,Y,T);
zlim([-3,6])

Answer 2

[Catalytic]

If I had to guess, you have x and y reversed.

[X, Y] = ndgrid(x, y);
surf(X, Y, t(X,Y));

[Dinh Le Dung]

i dont think so :((, but thanks for your help!