% S1 Function
% Range of initial points: -10 <= x <= 10
% Two global minimum: x={1,2}
% f(x)=0
% Coded by: Ali R. Alroomi | Last Update: 05 July 2015 | www.al-roomi.org
 
clear
clc
warning off
 
xmin=-10;
xmax=10;
R=100000; % steps resolution
x=xmin:(xmax-xmin)/R:xmax;
 
for i=1:length(x)
    f(i)=(x(i)-1)^2*(x(i)-2)^2;
end
 
plot(x,f,'r','LineWidth',2);grid;axis([0.5 2.5 0 0.55]);
xlabel('x','FontName','Times','FontSize',20,'FontAngle','italic');
ylabel('f(x)','FontName','Times','FontSize',20,'FontAngle','italic');