Fie expresia E(x) = [tex]\frac{x-3}{x+3}[/tex] · ([tex]\frac{1}{x-3}[/tex] - [tex]\frac{1}{x+3}[/tex] ) : [tex](x+3)^{-2}[/tex]
a) Determinati multimea A = { x ∈ R ; E(x) are sens }
b) Aratati ca expresia E(x) are valoarea constanta , oricare ar fi x ∈ A.