I wrote the code to plot two dimension graph but it is not showing the correct graph.So can you check and tell me where the mistake is in the code.

ploting two dimensional graph for u(x,t)=x*exp(-t)+exp(-x)

x=linspace(0,1,6);
y=linspace(0,1,6);

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

z=x*exp(-y)+exp(-x);
mesh(x,y,z);

Answer 1

[Star Strider]

I created an anonymous function for ‘z’, that illustrates what you need to do to plot your function.

This works:

x=linspace(0,1,6);
y=linspace(0,1,6);

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

z = @(x,y) x.*exp(-y)+exp(-x);

mesh(x,y,z(X,Y))

You need to use the meshgrid-created ‘X’ and ‘Y’ matrices to calculate ‘z’. You also need to use element-wise multiplication. See the documentation on Array vs. Matrix Operations for element-wise operations, and on Anonymous Functions for them.

You may also need to use the ‘X’ and ‘Y’ matrices in your mesh call. In recent MATLAB releases you can use the vectors. The alternative is:

mesh(X,Y,z(X,Y))

[YOGESHWARI PATEL]

x = linspace(-10,10 ,51)';
y = linspace(0,0.3,51)';
[X, Y] = meshgrid(x, y);
Z=X/(1+Y);
surf(X, Y, Z);
ylabel('t');
xlabel('x');
zlabel('u(x,t)')

Now its showing error Warning: Matrix is singular to working precision. and graph is not display.

[Star Strider]

You need to use element-wise operations, as I mentioned in my original Answer.

Try this:

Z=X./(1+Y);

Note the ‘./’ denoting element-wise division, instead of ‘/’ denoting matrix right-division.

Answer 2

[Walter Roberson]

x = linspace(0, 1, 6);
y = linspace(0, 1, 6);

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

Z = X .* exp(-Y) + exp(-X);
mesh(X, Y, Z);

[YOGESHWARI PATEL]

I am using R2013 version will command remain same.

[Walter Roberson]

Yes.

[JEYGANESH JAYA KUMARAN]

Hi, by using the above code, how to find value at a specific point in the mesh?