The phase-plane equation of a single-degree-of-freedom system is given by [frac{d y}{d x}=frac{-c y-left(x-0.1 x^{3} ight)}{y}] Investigate

The phase-plane equation of a single-degree-of-freedom system is given by

\[\frac{d y}{d x}=\frac{-c y-\left(x-0.1 x^{3}\right)}{y}\]

Investigate the nature of singularity at \((x, y)=(0,0)\) for \(c>0\).