Copyright © 2012 Iulia Costin and Gheorghe Toader. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Seiffert has defined two well-known trigonometric means denoted by and . In a similar way it was defined by Carlson the logarithmic mean as a hyperbolic mean. Neuman and Sándor completed the list of such means by another hyperbolic mean . There are more known inequalities between the means , and and some power means . We add to these inequalities two new results obtaining the following nice chain of inequalities , where the power means are evenly spaced with respect to their order.