Question

The ROC of z-transform of the discrete time sequence x(n) = is:

(a) 1/3>|z|<1/2

(b) |z|>1/2

(c) |z|<1/3

(d) 2>|z|<3

I got this question in a national level competition.

Question is from The Z-Transform in division Digital Control Systems of Control Systems

Answer 1

Correct choice is (a) 1/3>|z|<1/2

Easiest explanation: One part of the equation is the right sided signal and other part is the left sided signal hence the ROC of the system will be 1/3>|z|<1/2.