On the Normal Stability of Functional Equations

the effect of functional/notional approach on the proficiency level of efl learners and its evaluation through functional test

in fact, this study focused on the following questions: 1. is there any difference between the effect of functional/notional approach and the structural approaches to language teaching on the proficiency test of efl learners? 2. can a rather innovative language test referred to as "functional test" ge devised so so to measure the proficiency test of efl learners, and thus be as much reliable an...

On the Stability of Trigonometric Functional Equations

On the Stability of Monomial Functional Equations

In the present paper a certain form of the Hyers–Ulam stability of monomial functional equations is studied. This kind of stability was investigated in the case of additive functions by Th. M. Rassias and Z. Gajda.

Orthogonal stability of mixed type additive and cubic functional equations

In this paper, we consider orthogonal stability of mixed type additive and cubic functional equation of the form $$f(2x+y)+f(2x-y)-f(4x)=2f (x+y)+2f(x-y)-8f(2x) +10f(x)-2f(-x),$$ with $xbot y$, where $bot$  is orthogonality in the sense of Ratz.

Stability of the seventh-order functional Equations in the β-Gaussian space

The purpose of this paper is to solve the seventh-order functional equation as follows:  --------------------------- Next, we study the stability of this type of functional equation. Clearly, the function ----------  holds in this type functional equation. Also, we prove Hyers-Ulam stability for this type functional equation in the β-Gaussian Banach space.