Real analysis

[RichyZ2002]

I have a hard time understanding the Bolzano Weierstrass theorem. Help would be appreciated
Question: What does the Bolzano Weierstrass theorem tell you about the following sets:
a) e^(− cos n) : n ∈ N}
b) tan (π/(2n+1)) : n ∈ N

 

[Zermelo]

The BW theorem states that every bounded sequence has a convergent subsequence. Are those sets (sequences) bounded? If so, what does the BW theorem imply?