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% Assume function f(x,y)=-(x^2-2)^2 - (x^2-exp(y))^2
% Better Method
x = -5:.2:5;
y = 1:.2:4;

x_2d = ones(length(y),length(x))*diag(x);
y_2d = diag(y)*ones(length(y),length(x));

func = -(x_2d.^2-2).^2 - (x_2d.^2-exp(y_2d)).^2;

figure;hold on;grid on;

xlabel('x');ylabel('y');zlabel('f');
surf(x,y,func);

hold off;