Geodesic
A Functional Equation with Differences
Let $R$ denote the set of real number. Let us determine all functions $f:R\rightarrow R$ such that $\frac{f(tx+ty(-f(tx)}{f(tx)-f(tx-ty)}=\frac{f(x+y)-f(x)}{f(x)-f(x-y)}$ for all $x,y,t\in R,\;\;yt\neq 0$. This problem is due to P. Drṟeve{a}gilṟeve{a} [1]. 
@article{ZR_1976_1_9_a7,
     author = {Gyula Maksa},
     title = {A {Functional} {Equation} with {Differences}},
     journal = {Zbornik radova},
     pages = {49 },
     publisher = {mathdoc},
     volume = {1},
     number = {9},
     year = {1976},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ZR_1976_1_9_a7/}
}
TY  - JOUR
AU  - Gyula Maksa
TI  - A Functional Equation with Differences
JO  - Zbornik radova
PY  - 1976
SP  - 49 
VL  - 1
IS  - 9
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/ZR_1976_1_9_a7/
LA  - en
ID  - ZR_1976_1_9_a7
ER  - 
%0 Journal Article
%A Gyula Maksa
%T A Functional Equation with Differences
%J Zbornik radova
%D 1976
%P 49 
%V 1
%N 9
%I mathdoc
%U http://geodesic.mathdoc.fr/item/ZR_1976_1_9_a7/
%G en
%F ZR_1976_1_9_a7
Gyula Maksa. A Functional Equation with Differences. Zbornik radova, Tome 1 (1976) no. 9, p. 49 . http://geodesic.mathdoc.fr/item/ZR_1976_1_9_a7/