function [] = secant_method()
cn = [1,-1,-2];
a = 1.5;
b = 2.5;
k = 1;

n(k) = (polyval(cn,b)*a - polyval(cn,a) *b )/ (polyval(cn,b)- polyval(cn,a));

%if (round(n(k),1) == 2)
    n(k),
%end


approximate_error(k) = abs(n(k) - 2)/2,
k=k+1;

n(k) = (polyval(cn,n(k-1))*b - polyval(cn, b) * n(k-1))/ (polyval(cn, n(k-1)) - polyval(cn,b));

%if(round(n(k),1) == 2)
    n(k),
%end


approximate_error(k) = abs(n(k) - 2)/2,

while(k < 10)
    n(k+1) = polyval(cn, n(k))*n(k-1) - polyval(cn,n(k-1)*n(k))/ (polyval(cn, n(k)) - polyval(cn,n(k-1)));

    approximate_error(k+1) = abs(n(k+1) - 2)/2,
    n(k+1),
    k=k+1;
end