Hi,
I beleive you wish to plot the 'Rosenbrock function '. Please refer to a simple example provided below.
x_int = [0 1];
y_int = [0 1];
[X Y] = meshgrid(linspace(x_int(1),x_int(2),150),linspace(y_int(1),y_int(2),150));
mask = X.^2 + Y.^2 <=1; %extracting points on grid where condition fails
X(~mask) = nan; %putting values of invalid x and y as nan
Y(~mask) = nan;
myFun = @(X,Y) (100*(Y-X.^2).^2 + (1 - X).^2); %creating function handle for equation of Rosenbrock function
mesh(X,Y,myFun(X,Y)); %plotting on mesh grid
var_values = myFun(X,Y); %extract the points within rosenbroke function