function jsdd(x,y,e,f)
f1=inline(f);
syms a
a1=diff(f1(a));
f2=inline(a1);
xx=linspace(x,y,100);
s=abs(f2(xx));
s1=zeros(1,100);
s2=ones(1,100);
if s>s1 & s<s2;
    i=0;
    while abs(x-y)>e;
    y=f1(x);
    z=f1(y);
    x=z-(z-y)^2/(z-2*y+x);
    i=i+1;
    fprintf('%d%13.8f\n',i,x);
    end
else 
        disp('此多項式不能進行迭代');
end
%function xia329(a,b,j,f3)
%f=inline(f3);
%syms x
%y=diff(f(x));
%f2=inline(y);
%xx=linspace(a,b,100);
 %   s=abs(f2(xx));
  %  s1=zeros(1,100);
   % s2=ones(1,100);
    %if s>s1 & s<s2;
     %   i=1;
      %  while abs(a-b)>j;
       %     a=b;
        %    b=f(a);
         %   i=i+1;
          %  fprintf('%d%13.8f\n',i,b);
          %        end
          %  else 
       % disp('此多項式不能進行迭代');
       %end