function newi = newi(f,n,z0)
%UNTITLED9 Summary of this function goes here
%   Detailed explanation goes here
syms z;
df= diff(f);
z=z0;

Z=zeros(n,1);
Z(1)=z0;
    
for k=2:n
    
    
        Z(k)=Z(k-1)-eval(f)/eval(df);
    
        z=Z(k);
            
        k=k+1;


end
       
      
    
 



plot([1:n],Z,'.')

Z
hold on
size(Z)

end