Evaluate the following limits :
`lim_(x rarr 1) [1/(x-1)-2/(x^2-1)]`

Explanation

To evaluate the limit \( \lim_{x \to 1} \left[ \frac{1}{x-1} - \frac{2}{x^2-1} \right] \), we will follow these steps:

### Step 1: Rewrite the expression
We start with the expression:
\[ \frac{1}{x-1} - \frac{2}{x^2-1} \]
Notice that \( x^2 - 1 \) can be factored as \( (x-1)(x+1) \). Thus, we can rewrite the second term:
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