Tính các giới hạn sau: lim x suy ra 1 ((x - 1) / (x^2 - 1))

\(\mathop {\lim }\limits_{x \to 1} \frac{{x - 1}}{{{x^2} - 1}}\)\( = \mathop {\lim }\limits_{x \to 1} \frac{{x - 1}}{{\left( {x - 1} \right)\left( {x + 1} \right)}} = \mathop {\lim }\limits_{x \to 1} \frac{1}{{x + 1}} = \frac{1}{2}\).