t = linspace(0,3);
y = (2-t.^2).^2;
figure; plot( t, y, '-o' );

disp( 'Truth is:' );
sqrt(2)

% A:
x(1) = 1.5;
for i=2:5,
  x(i) = x(i-1) + 4*(0.1/(i-1))*x(i-1)*(2-x(i-1)^2);
end
x

% B: 
x(1) = 1.5;
for i=2:5,
  x(i) = x(i-1) + 4*(0.1)*x(i-1)*(2-x(i-1)^2);
end
x

% C: 
x(1) = 1.5;
for i=2:5,
  x(i) = x(i-1) + 4*x(i-1)*(2-x(i-1)^2);
end
x