1.
If the function ff defined on R\mathbb{R} by
f(x)={2cosx1cotx1,xπ4k,x=π4f(x) = \begin{cases} \frac{\sqrt{2}\cos x - 1}{\cot x - 1}, & x \neq \frac{\pi}{4} \\ k, & x = \frac{\pi}{4} \end{cases}
is continuous, then kk is equal to