On the stability of some functional equations. (English) Zbl 0844.39007

Rassias, Themistocles M. (ed.) et al., Stability of mappings of Hyers-Ulam type. Palm Harbor, FL: Hadronic Press, 93-98 (1994).
Summary: We give a new method to prove the stability of the cosine equation and with this method we obtain a result concerning the stability of the Lobachevski equation.
For the entire collection see [Zbl 0835.00001].


39B82 Stability, separation, extension, and related topics for functional equations
39B32 Functional equations for complex functions