MathDB

7

Part of 2011 QEDMO 9th

Problems(1)

f(xy + x + y) + f(xy-x-y)=2f (x) + 2f (y)

Source: 9th QEDMO p7 Seniors (21-22. 9. 2011) https://artofproblemsolving.com/community/c1512515_qedmo_200507

5/15/2021
Find all functions f:R→Rf: R\to R, such that f(xy+x+y)+f(xy−x−y)=2f(x)+2f(y)f(xy + x + y) + f(xy-x-y)=2f (x) + 2f (y) for all x,y∈Rx, y \in R.
functional equationfunctionalalgebra