Following are four z-transforms. Determine which ones could be the z-transform of a causal sequence. Do not evaluate the inverse transform. You should be able to give the answer by inspection. Clearly state your reasons in each case.

Transcribed Image Text:

(1-z)2 (a) (1 – { 1) (z - 1)2 (b) († - 2) (2 - )* (c) (: - !)" (:- 4) (: - !)* (d)