Newton.m
function [x_star,index,num]=Newton(fun1,fun2 ,x,ep,maxnum)
if nargin<5 maxnum=100; end
if nargin<4 ep=1E-5;end
index=0;k=1;
while k<=maxnum
    x1=x;
    f=zeros(1,2);
    f(1)=feval(fun1,x);
    f(2)=feval(fun2,x);
    if(abs(f(2))<ep)
        break;
    end
    x=x-f(1)/f(2);
    if(abs(x-x1)<ep)
        index=1;break;
    end
    k=k+1;
end
x_star=x;
num=k;
end