Find the range of f(x)=xx2+1f(x) = \frac{x}{x^2+1}f(x)=x2+1x for x∈Rx \in \mathbb{R}x∈R.
[−1,1][-1, 1][−1,1]
[−12,12][-\frac{1}{2}, \frac{1}{2}][−21,21]
[0,1][0, 1][0,1]
(−∞,∞)(-\infty, \infty)(−∞,∞)