where $A$ and $p$ are constant.
The period of small oscillations of the particle is
$\mathrm{F}=-\frac{\mathrm{d} \mathrm{V}}{\mathrm{dx}}=-\mathrm{Ap} \sin \mathrm{px}$
for small displacement
$\sin \mathrm{px}=\mathrm{px}$
$\therefore \mathrm{F}=-\mathrm{Ap}^{2} \mathrm{x}$
$\mathrm{T}=2 \pi \sqrt{\frac{\mathrm{m}}{\mathrm{K}}}=2 \pi \sqrt{\frac{\mathrm{m}}{\mathrm{Ap}^{2}}}$