On entire solutions of two kinds of quadratic trinomial Fermat type functional equations

Abstract

The existence of entire solutions to Fermat type differential-difference equations and \(q\)-difference differential equations involving second-order derivatives is investigated by using Nevanlinna theory. The exact forms of the entire solutions to these equations mentioned above are identified. These results represent a generalization and improvement of previous findings obtained by Gong et al. [Bull. Iran. Math. Soc. 51, 17 (2025)]. Furthermore, some examples are provided to illustrate these results.