Answer
$$\infty$$
Work Step by Step
We evaluate the limit:
\begin{align*}
\lim _{x \rightarrow 1+}\left(\frac{1}{\sqrt{x-1}}-\frac{1}{\sqrt{x^{2}-1}}\right)&=\lim _{x \rightarrow 1+} \frac{\sqrt{x+1}-1}{\sqrt{x^{2}-1}}\\
&=\infty
\end{align*}