The potential energy of a 1 kg particle free to move along the $x$-axis is given by
$$V(x) = \left(\frac{x^4}{4} - \frac{x^2}{2}\right) \text{J}$$
The total mechanical energy of the particle is 2 J. Then, the maximum speed (in m/s) is\\
(1) 2\\
(2) $3/\sqrt{2}$\\
(3) $\sqrt{2}$\\
(4) $1/\sqrt{2}$