clc, clear all;
x0=0;
allaDiff=[]
diffold=1;
for i=1:15
    x1=1/3*(x0^2+1);
    diff =x1-x0;
    allaDiff=[allaDiff; diff];
    diffminskning=diff/diffold;
    disp(diffminskning)
    diffold=diff;
    x0=x1;
end
allaDiff
allaDiff(end-4:end)./allaDiff(1:5)