Răspuns :
f(2009/2008)=2008·2009/2008-2007=2009-2007=2; pct A(2009/2008;2) ∈ Gf.
trb ca f(2009/2008)=2
f(2009/2008)=2008*2009/2008-2007=2
deci apartine
f(2009/2008)=2008*2009/2008-2007=2
deci apartine