If the function
\[
f(x)=\begin{cases}\frac{e^{b(x-1)^{2}}-1}{\sqrt{x^{2}-1}} & , \text{for } x>1 \\ \sqrt{2} & , \text{for } x=1 \\ \log\left(\frac{1+bx}{1-bx}\right)\frac{1}{\sin^{2}x} & , \text{for } 0<x<1 \end{cases}
\]
is continuous at \( x=1 \), then \( \lim_{x \rightarrow 2} \frac{x^{2}-5x+6}{x-2} = \)