Consider the function f(x)={x2−1x−1x≠1kx=1f(x) = \begin{cases} \frac{x^2-1}{x-1} & x \neq 1 \\ k & x = 1 \end{cases}f(x)={x−1x2−1kx=1x=1. For what value of kkk is fff continuous at x=1x=1x=1?
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