Need help creating an 2-D 400×300 array

Need help creating a meshgrid() to create a 2-D 400×300 array of numbers. I want to design an interesting function like the product of two sine functions using the array values as inputs. I want to a create a grayscale image of this function with imagesc(). and also add a colorbar and label both axes. I also need to change the values of the array elements [100:110, 50:60] to make something that will be visible in the image. Much appreciated for the help.

[madhan ravi]

What have we tried so far?

[JC]

My first method was to create these arrays. One 400x300 array.

A = repmat(1:400,300,1)

B = repmat(100:110,50,60)

Another method for the meshgrid part that I followed

colormap('gray')

nx=300;

x=-nx/2:nx/2-1;

ny=400;

y=-ny/2:ny/2-1;

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