I was reading a text book on the frequency domains in signal processing and my understanding is that the Fourier Transform considers signals that are a-periodic in time while the Fourier Series considers periodic signals in time (such as a sum of sinusoids).
But the book clearly mentions that the FS can be seen as a special case of the FT and that doesn't make sense to me.
My understanding is that the FT is a special case of FS where periodicity is just infinity. But the book says its the other way around without providing its own reasoning.
It makes no sense and I can't find answers online