  Generalized trigonometric functions and generalized hyperbolic functions can
be converted to each other by the duality formulas previously discovered by the
authors. In this paper, we apply the duality formulas to prove dual pairs of
Wilker-type inequalities, Huygens-type inequalities, and (relaxed)
Cusa-Huygens-type inequalities for the generalized functions. In addition,
multiple- and double-angle formulas not previously obtained are also given.
