The following is known about a discrete – time LTI system with input x[n] and output y[n] :

1)  If for all n , then y[n] = 0 for all n.

2)  If for all n , then y[n] for all n is of the form ,

where a is a constant.

(a)  Determine the value of the constant a .

(b)  Determine the response y[n] if the input x[n] is x[n] =1 for all n.