Two different answers while doing Inverse Z-transform

1. What are different methods of inverse Z-transform?
2. How many types of Z-transform are there?
3. What is the inverse Z-transform of 1 z?

What are different methods of inverse Z-transform?

There are at least 4 different methods to do this: Inspection. Partial-Fraction Expansion. Power Series Expansion.

How many types of Z-transform are there?

The Z-transform may be of two types viz. unilateral (or one-sided) and bilateral (or two-sided). Where, r is the radius of a circle. The unilateral or one-sided z-transform is very useful because we mostly deal with causal sequences.

What is the inverse Z-transform of 1 z?

The Z-transform of a sequence an is defined as A(z)=∑∞n=−∞anz−n. In your case, A(z)=1/z=z−1, so this must mean an=0 for all n≠1, and a1=1. We don't need any fancy computations in this example, we just read off the one nonzero coefficient directly from A.