Saturday, 20 September 2014

sequences and series - Proving that every trap is a lure



I am using the book "Learn Limits Through Problems". It states that an interval on a infinite sequence is a "trap" if a finite terms lie outside the interval while an interval will be called a "lure" if an infinite amount of terms lie within the interval. If I'm using the harmonic series as an example, I would think that the whole interval would be considered a trap since there are finite amount of terms (0) outside the interval. It also makes sense that this whole interval would be considered a lure since there are infinite points within the sequence. However, I am not sure how to formally prove this. Any hints will be appreciated. Thanks.


Answer




Suppose I have infinitely many beads (terms in the sequence) and a basket (interval). I put some beads in the basket and leave some outside. If there are only finitely many beads left outside (basket is trap) then how many must have been put inside?


No comments:

Post a Comment

real analysis - How to find $lim_{hrightarrow 0}frac{sin(ha)}{h}$

How to find $\lim_{h\rightarrow 0}\frac{\sin(ha)}{h}$ without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...