If the function f(x)= {(log_e (1-x+x^2)+ log_e (1+x+x^2))/(sec x- cos x), x ∈((-π)/2, (π)/2)-{0}; k, x=0} is continuous at x=0, then k is equal to:

If the function $\displaystyle f(x)=\left\{\begin{array}{cc}\frac{\log _{\mathrm{e}}\left(1-x+x^2\right)+\log _{\mathrm{e}}\left(1+x+x^2\right)}{\sec x-\cos x} & , x \in\left(\frac{-\pi}{2}, \frac{\pi}{2}\right)-\{0\} \\ \mathrm{k} & , x=0\end{array}\right.$ is continuous at $\displaystyle x=0$, then k is equal to :