hi,
may i know what is the difference notation wise when i say
a sequence x_n or <x_n> or {x_n}?
There is no difference. The important thing is that a sequence (for example on $\displaystyle \mathbb{R}$) is a map:
$\displaystyle f:\mathbb{N}\rightarrow{\mathbb{R}}$
and we denote wifhout distinction $\displaystyle f$ by $\displaystyle x_n,\;<x_n>$ or $\displaystyle \{x_n\}$ ( $\displaystyle x_n:=f(n)$ ) .
Regards.
Fernando Revilla