Notes on the diamond-α dynamic derivative on time scales

Various dynamic derivative formulae have been proposed in the development of a time scales calculus, with the goal of unifying continuous and discrete analysis. Recent discussions of combined dynamic derivatives, in particular the ♦α derivative defined as a linear combination of the and the ∇ derivatives, have promised improved approximation formulae for computational applications. This paper presents an equivalent definition of the ♦α functions without reference to the existing and ∇ derivatives, examines the status of the ♦α as a dynamic derivative and its properties relative to the and ∇ derivatives, and compares data obtained using the various dynamic derivatives as approximation formulae in computational experiments. A ♦α integral case is investigated. © 2006 Elsevier Inc. All rights reserved.