Determine the range of xxx for which the inequality x2−1x2+1≤0\frac{x^2 - 1}{x^2 + 1} \leq 0x2+1x2−1≤0 is satisfied.
x∈Rx \in \mathbb{R}x∈R
x∈(−1,1)x \in (-1, 1)x∈(−1,1)
x∈[−1,1]x \in [-1, 1]x∈[−1,1]
x∈(−∞,−1]∪[1,∞)x \in (-\infty, -1] \cup [1, \infty)x∈(−∞,−1]∪[1,∞)