Fast Fourier Transform of a Cosine Summation Function resonating at 10, 20, 30, 40, and 50 Hz
<a href="//commons.wikimedia.org/wiki/User:AkanoToE" title="User:AkanoToE">AkanoToE</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>