Error: Z must be a matrix, not a scalar or vector and error in solution (line 12): surf(x,y,z);

1 %Set the Domain of both x and y by setting the lower limit 
2 a = 0                      %Enter the lower limit of both x and y in the domain of the sketch
3 b = 0                      %Enter the upper limit of both x and y in the domain of the sketch
4 h = 0.05                      %Identify the increment
5 
6 %Setup the graphing properties for both x and y and z.
7 [x,y] = meshgrid(a:h:b);                                %Create the domain of the graph 
8 z = -x^4+x^2-y^2                  %Encode the function in terms of x and y (Note that all operations between x's and y's are done with dotted operation
9
10 %First Plotting Space.  Sketch the surface with the title "Surface Plot"
11 subplot(2,1,1);                                %Divide the plotting space into Four parts and use the first plotting area
12 surf(x,y,z);                                %Plot the given surface
13 title("Surface Plot");                                %Set the title as "Surface Plot"
14                                
15 %Second Plotting Space.  Sketch the Mesh with the title "Mesh Plot"
16 subplot(2,2,2);                                %First PLotting Space.  Sketch the surface with the title "Surface Plot"
17 mesh(x,y,z);                                %Use the second plotting space
18 title("Mesh Plot");                                %Mesh Plot the given surface
19                                %Set the title as "Mesh Plot"
20
21 %Third Plotting Space.  Sketch the Level Curves at various heights with the title "Level Curves"
22 subplot(2,2,3);                                %Use the third plotting space
23 contour3(x,y,z);                                %Plot the Level Curves of the given surface
24 title("Level Curves");                                %Set the title as "Level Curves"
25 grid on                                %Set Grid On
26
27 %Fourth Plotting Space.  Sketch the Contour Map with the title "Contour Plot"
28 subplot(2,2,4);                                %Use the fourth plotting space
29 contour(x,y,z);                                %Plot the Level Curvesof the given surface
30 title("Contour Plot");                                %Set the title as "Contour Plot"
31 axis equal                                %Set Grid On
32 grid on                                %Set the Axes to have the same scale 
33
34 %Start Using Rotate 3D Tools to rotate the solids

Error: 

Error using surf
Z must be a matrix, not a scalar or vector.

Error in solution (line 12)
surf(x,y,z);         %Plot the given surface

Answer 1

[Chunru]

Change the value of b:

 
%Set the Domain of both x and y by setting the lower limit 
 a = 0                      %Enter the lower limit of both x and y in the domain of the sketch

a = 0

 
 %   VVV  use a bigger b so that x, y have more points 
 b = 10                      %Enter the upper limit of both x and y in the domain of the sketch

b = 10

 
 h = 0.05                      %Identify the increment

h = 0.0500

 %Setup the graphing properties for both x and y and z.
 [x,y] = meshgrid(a:h:b);                                %Create the domain of the graph 
 z = -x^4+x^2-y^2;                  %Encode the function in terms of x and y (Note that all operations between x's and y's are done with dotted operation
 %whos

 %First Plotting Space.  Sketch the surface with the title "Surface Plot"
 subplot(2,2,1);                                %Divide the plotting space into Four parts and use the first plotting area
 surf(x,y,z);                                %Plot the given surface
 title("Surface Plot");                                %Set the title as "Surface Plot"
                                
 %Second Plotting Space.  Sketch the Mesh with the title "Mesh Plot"
 subplot(2,2,2);                                %First PLotting Space.  Sketch the surface with the title "Surface Plot"
 mesh(x,y,z);                                %Use the second plotting space
 title("Mesh Plot");                                %Mesh Plot the given surface
                                %Set the title as "Mesh Plot"

 %Third Plotting Space.  Sketch the Level Curves at various heights with the title "Level Curves"
 subplot(2,2,3);                                %Use the third plotting space
 contour3(x,y,z);                                %Plot the Level Curves of the given surface
 title("Level Curves");                                %Set the title as "Level Curves"
 grid on                                %Set Grid On

 %Fourth Plotting Space.  Sketch the Contour Map with the title "Contour Plot"
 subplot(2,2,4);                                %Use the fourth plotting space
 contour(x,y,z);                                %Plot the Level Curvesof the given surface
 title("Contour Plot");                                %Set the title as "Contour Plot"
 axis equal                                %Set Grid On
 grid on                                %Set the Axes to have the same scale 

 %Start Using Rotate 3D Tools to rotate the solids

[Girb]

Thank you kind sir