Department of Mathematics, Babeş-Bolyai University, Strada Kogălniceanu no. 1,
400084 Cluj-Napoca, Romania
Copyright © 2012 József Sándor. 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.
By using the theory of means, various refinements of Huygens' trigonometric and hyperbolic inequalities will be proved. New Huygens' type inequalities will be provided, too.