What is the ROC of Y(z) in this Z transform ?

[sweetsalt]

help required

The input to causal LTI system is
x[n] = u[-n-1]+(0.5)^n u[n]


the Z transform of the output of this system is

Y(Z) = -1/2 Z^-1 whole divided by (1-0.5z^ -1)(1+z^-1)

a) determine H(z) the transform of the system impulse respone.Be sure to specify the ROC.

b) what is the ROC of Y(z)?
c) determine y

answer to part a is H(Z)= 1-z^ -1 / 1 + z^-1 roc = |z| > 1 ... iss part ke samjh lag gaye hey.


b ) ROC { Y(Z) } = |Z| > 1 ... i am really unable to understand this, how?

 

[MSGHP]

help required

The output of a causal system is causal too.
Y(Z) is the out put of a causal system so it must be right sided and its roc is out side of the outer most pole.