Giao luu:
\(y=\sqrt{\frac{2+x}{2-x}}\)
\(\left\{\begin{matrix}\left\{\begin{matrix}-2\le x< 2\\f\left(x\right)=\sqrt{\left(\frac{2+x}{2-x}\right)}\end{matrix}\right.\\\left\{\begin{matrix}-2< x\le2\\f\left(-x\right)=\sqrt{\left(\frac{2-x}{2+x}\right)}=\sqrt{\frac{1}{\left(\frac{2+x}{2-x}\right)}}=\frac{1}{\sqrt{\left(\frac{2+x}{2-x}\right)}}=\frac{1}{f\left(x\right)}\end{matrix}\right.\end{matrix}\right.\)
\(\left\{\begin{matrix}!x!< 2\\f\left(x\right).f\left(-x\right)=1\end{matrix}\right.\)
kết luân: y không chẵn không lẻ