We answer the question: for any with and , what are the greatest value and the least value , such that the double inequality holds for all with ? Where is the th power mean of two positive numbers and .
Yong-Min Li. Bo-Yong Long. Yu-Ming Chu. "A Best Possible Double Inequality for Power Mean." J. Appl. Math. 2012 1 - 12, 2012. https://doi.org/10.1155/2012/379785