function xx = newt(f, x0, eps, maxi)

syms x;

fp = diff(f,x);
 

stp = 0;
for i = 1:maxi
    ff = subs( f, x, x0);    
    dd = subs(fp, x, x0);
    x0 = x0 - ff/dd;
    if abs(ff) < eps
        stp = 1;
        break;
    end
end

if stp == 1
    xx = x0;
else
    xx = 'too many iterations';
end