Solve 1x2−4<1\frac{1}{x^2 - 4} < 1x2−41<1.
(−∞,−2)∪(2,∞)(-\infty, -2) \cup (2, \infty)(−∞,−2)∪(2,∞)
(−∞,−5)∪(−2,2)∪(5,∞)(-\infty, -\sqrt{5}) \cup (-2, 2) \cup (\sqrt{5}, \infty)(−∞,−5)∪(−2,2)∪(5,∞)
(−∞,−2)∪(−2,2)∪(2,∞)(-\infty, -2) \cup (-2, 2) \cup (2, \infty)(−∞,−2)∪(−2,2)∪(2,∞)
(−∞,−5)∪(5,∞)(-\infty, -\sqrt{5}) \cup (\sqrt{5}, \infty)(−∞,−5)∪(5,∞)