Think of a graph of exponential when r < 0. It decreases, so does cosine amplitude in this envelope. So it is not like e^rt will have both upper and lower parts of the envelope, but rather exponential nature will create them.

That’s because FS and FT have even and odd part too

I posted some critical comments on Lec 01 and it got deleted (presumably by the owner of the channel) after a few minutes 🤣. If you want your comments to be not deleted, sing paeans 🤣🤣. Even this comment will most likely get deleted!!

@@vvanamali6286 It is a free course. If you don't have anything nice to say, don't say it. It's not like you are paying the guy. So why should he listen to your whining?

@@hedgehog_fox It is silly to state that only "nice comments" should be posted. In the comment of mine that was deleted, I had pointed out things that were either misleading or incorrect. Examples: (i) x[a] when 'a' is not an integer is undefined and not zero. This point is glossed over when defining quantities like x[n/3], and (ii) while defining the derivative of u(t), it is being implied that delta(t) = infinity at t=0. This is wrong. Yes, the video is free. You seem to imply that misleading stuff can therefore be part of its content. Actually, if misleading stuff is posted, it should be called out so that those who are learning don't gulp it down unquestioningly. Without even knowing the contents of the deleted comment, you have been gratuitously labelled my response as "whining". Oh well.

I immediately hear the aliasing on the background