%secant method
function [x]=dejen_secant_2019(f, x1, x2, tol)
%format compact% long
x(1)=x1;
x(2)=x2;
fprintf(' n       x(n-1)         x(n)      f(x(n))     |x(n)-x(n-1)|\n');
fprintf('==============================================================\n');
for n=3:100
    x(n) = x(n-1) - f(x(n-1))*((x(n-1) - x(n-2))/(f(x(n-1)) - f(x(n-2))));
    if abs(x(n)-x(n-1))<tol; 
        break; 
    end
    fprintf('%2d  %12.8f  %12.8f  %12.8f  %12.8f\n',n,x(n-1),x(n), f(x(n)),abs(x(n)-x(n-1)));
 
end