The potential energy function of a particle of mass m is $\displaystyle V=\frac{-1}{2}c(x^2-a^2)^2$, where a,c > 0. Sketch V as a function of x and describe the possible types of motion in the three cases (a) E > 0, (b) $\displaystyle E < \frac{-1}{2}ca^4$ and (c) $\displaystyle \frac{-1}{2}ca^4< E < 0$

I can sketch the graph which gives you an upside-down parabola, but i cannot see how to determine the motion, i think it have something to do with T+V=E (conservation of energy)