我想在matlab上做求和，误差不超过10的-5次方。代码如下，求dalao指导

sum = 0;
for n=1:100
a=n.^(-(1/3));
b=(n+1).^(-(1/3));
c=b-a;
if c>10^(-5)
sum = sum + n^(-(1/3));
end
end

sum = 0;
for n=1:100
    a=n.^(-(1/3));
    b=(n+1).^(-(1/3));
    c=abs(b-a);
    if c>10^(-5)
        sum = sum + n^(-(1/3));
    end
end
sum