
accumulation point help
How do you determine the accumulation point of a set?
For example,
What is the accumulation point of $\displaystyle z_{n}$ = $\displaystyle i^n$ where n $\displaystyle \in$ $\displaystyle Z^+$
And what is the accumulation point of the following?
(a) $\displaystyle z_{n}$ = $\displaystyle i^n$/n where n $\displaystyle \in$ $\displaystyle Z^+$
(b) 0 $\displaystyle \leq$ arg(z) < $\displaystyle \pi$/2 and z not equal to 0
(c) $\displaystyle z_{n}$ = $\displaystyle (1)^n$(1+ i ) (n1)/n where n $\displaystyle \in$ $\displaystyle Z^+$
Any help? Thanks!