I am stuck with this question. I have to calculate the limit

my formula is .. This is final value theorem of Z transform

f(infinity) = limit (z-->1) [ 1- z^ -1] x [ 1/( 1+ z^ -2]

How to solve this

second is

f(infinity) = limit (z-->1) [ 1- z^ -1] x [ z / (( z-1/2) (z-2))]