Watch & download why infinity does not exist MP4 and MP3 now. You can download free mp3 or MP4 as a separate song, or as video and download a music collection from any artist, which of course will save you a lot of time.
Here we show that a limit does not exist because it get arbitrarily close to anything. Limits of trigonometric functions.
Limits by expansion of series. This video explains the basic idea that limits do not exist if answer is infinity or negative infinity. Show that the limit(0,0) xy/(x^2 + y^2) does not exist by finding two curves in xyplane along which limit agree.