Determine the set of all real values xxx such that x2−4x2+1<x2+1x2−4\frac{x^2 - 4}{x^2 + 1} < \frac{x^2 + 1}{x^2 - 4}x2+1x2−4<x2−4x2+1.
x \in (-2, 2)
x \in (-\sqrt{5}, \sqrt{5}) \setminus {-2, 2}
x \in (-\infty, -2) \cup (2, \infty)
x \in (-\infty, -\sqrt{5}) \cup (\sqrt{5}, \infty)