x=linspace(-2,2);
y=x;
[X Y]=meshgrid(x,y);
pl=contourf(X,Y,ros(X,Y),-.5:10:150);
##axis([0 2 0 2]);
pause
hold on
plot(1,1,"og","markersize",10,"markerfacecolor","g")
plot(-1,1.8,"or","markersize",10,"markerfacecolor","r")
hold off
pause
  xold=[-1;1.8];
ops=optimset("fminunc");
ops=optimset(ops,"MaxIter",20);
for i=1:100
## caso 1: utilizando fminunc
##	xnew=fminunc(@rosenbrock0,xold,ops);
## caso 2: fazendo Newton na mao
[funcao grad hessiana]=rosenbrock(xold);
direcao=-hessiana\grad';
xnew=xold+direcao
pl=contourf(X,Y,ros(X,Y),-.5:10:150);
##axis([0 2 0 2]);
hold on
plot(1,1,"og","markersize",10,"markerfacecolor","g")
plot(xold(1),xold(2),"or","markersize",12,"markerfacecolor","r")
plot(xnew(1),xnew(2),"ow","markersize",10,"markerfacecolor","w")
hold off
pause
xold=xnew;
end