The amplitude of 15 ( 1000 ) is modulated by 10 ( 4 ) signal. The...

The carrier wave frequency is given by

$\begin{cases}{f}_{c} & = & \dfrac{1000\pi}{2\pi} \\ & = & 500Hz\end{cases}$

The modulating wave frequency is given by

$\begin{cases}{f}_{m} & = & \dfrac{4\pi}{2\pi} \\ & = & 2Hz\end{cases}$

Hence, the frequencies contained in the modulated signal are given by

$\begin{cases}f & = & {f}_{c} - {f}_{m}, {f}_{m}, {f}_{c} + {f}_{m} \\ = & 498Hz, 500Hz, 502Hz\end{cases}$