Conclusion:
There are so many applications for FFTs from solving differential
equations to radar and sonar, studying crystal structures, Wi-Fi and 5G.
Basically all kinds of signal processing use FFTs and that’s why
mathematician Gilbert Strang called the FFT the most important numerical
algorithm of our lifetime. If only it had become more widely adopted
after Gauss discovered it, the FFT may have even more dramatically
transformed our world.