Răspuns :
(f/g)'= (fg'-f'g)/g²= [(x+1)' * (x-1) - (x-1)' *(x+1)]/(x-1)²=
[1* (x-1) -1*(x+1)]/(x-1)²= (x-1-x-1)/(x-1)²= -2/(x-1)²
observam ca f'(x) <0 ∀x∈R\{1}, de asteptat, f(x) fiind functie omografica cu ab-cd=-2<0
f'(0)=-2/1=-2
[1* (x-1) -1*(x+1)]/(x-1)²= (x-1-x-1)/(x-1)²= -2/(x-1)²
observam ca f'(x) <0 ∀x∈R\{1}, de asteptat, f(x) fiind functie omografica cu ab-cd=-2<0
f'(0)=-2/1=-2