In order to plot a surface, you can use the below commands:
[X,Y] = meshgrid(1:0.5:10,1:20);
Z = sin(X) + cos(Y);
surf(X,Y,Z)
You can use the differentiation fucntion (https://www.mathworks.com/help/symbolic/differentiation.html) to differentiate, and can use the above code to plot the surface plot.