newton.m

牛顿迭代法求非线性方程

%牛顿法

x=1.5;
x1=x-fun(x)/gun(x);
if(abs(x1)<1)
    delt=abs(x1-x);
else
    delt=abs((x1-x)/x1);
end

while(delt>1e-6 & abs(gun(x))>1e-6)
    x=x1;
    x1=x-fun(x)/gun(x);
    if(abs(x1)<1)
        delt=abs(x1-x);
    else
        delt=abs((x1-x)/x1);
    end
    if gun(x1)==0
        break
    end         
end

b=x1;
fprintf('%.6f\n',b)