bstitute <img src="pix/fmeq23.png" alt="wct"> for "a" and
<img src="pix/fmeq9.png" alt="bsin">
for "b" and get:
</p>


<!-- LATEX \[  \cos (\omega_{c}t+B\sin \omega_{m}t)=\cos \omega_{c}t \, \cos (B \sin \omega_{m}t) - \sin \omega_{c}t \, \sin (B\sin \omega_{m}t)  \] -->

<img class="indented" src="pix/fmeq6.png" alt="cos (sin) expanded">


<p>If we can get a Fourier transform of the two inner portions: 
<img src="pix/fmeq41.png" alt="cos sin"> and
<img src="pix/fmeq40.png" alt="sin sin">, we can use:
</p>
