format long
x=[0,0];
x=input('請輸入初始值[x0,x1]=');
s=input('請輸入初始精度s＝');
g=D_F(x);
g=g.';%轉置為列向量；
k=1;
while(norm(g)>s)  
    s_k=Two_DF_1(x)*g;
    r=min_F(x,s_k);
    x=x+r.*s_k.';
    g=D_F(x);
    g=g.'; 
    fprintf('iteration step %d\n', k);
    fprintf('The result is %8.5f\n', x);    
    fprintf('The daosu is %8.5f\n', g);   
    k=k+1;
end