摘要 ZHAIYAO{运用实分析方法，研究了Neuman-Sándor平均M（a，b）与第二类反调和平均D（a，b）和调和根平方平均H（a，b）（及调和平均，H（a，b））凸组合的序关系.发现了最大值λ1，λ2∈（0，1）和最小值μ1，μ2∈（0，1）使得双边不等式 λ1D（a，b）+（1-λ1）H（a，b）0且a≠b成立.Abstract：This paper deals with the inequalities involving Neuman-Sándor means using methods of real analysis. The convex combinations of the second contra-harmonic mean D(a, b) and the harmonic root-square mean H(a, b) (or harmonic mean H(a,b)) for the Neuman-Sándor mean M(a, b) are discussed. We find the maximum values λ1, λ2 ∈ (0, 1) and the minimum values μ1, μ2 ∈ (0, 1) such that the two-sided inequalities λ1D(a, b) + (1-λ1)H(a, b) < M(a, b) < μ1D(a, b) + (1-μ1)H(a, b), λ2D(a, b) + (1-λ2)H(a,b) < M(a, b) < μ2D(a, b) + (1-μ2)H(a,b) hold for all a, b > 0 with a≠b.
