可以简单证明

送交者: 鹏归于 2009-05-26, 02:53:30:

回答: 我来补充一下HunHunSheng的论证由 wanxiang 于 2009-05-26, 01:47:27:

let m<M

(m+M)/(m^(2/3)+M^(2/3))=m^(1/3)*(m^(2/3)+(M/m)^(1/3)*M^(2/3))/(m^(2/3)+M^(2/3))>m^(1/3)

(m+M)/(m^(2/3)+M^(2/3))=M^(1/3)*((m/M)^(1/3)*m^(2/3)+M^(2/3))/(m^(2/3)+M^(2/3))<M^(1/3)