Z Transform problem ?

[Anders]

parisse, that would be great.

Here are some another thoughts:
The Student typically gets introduced to Z-transforms when taking a Discrete Control Theory or Digital Signal Processing course/topic. In these topics you would typically use the step function u[n] (u[n]=1 for n>=0 else =0) in time discrete domain and more seldom the δ[n] (except when doing invztrans(1) which is indeed = δ[n]). Hence, the student would be more familiar with what HP prime output if the answers were mostly formulated in terms of u[n] (where appropriate) rather than δ[n].

For the example above, the standard text book z-transform table entry the student would use in named courses would look something like this:

Time domain: b^(n-1)*u(n-1)
z-domain: 1/(z-b)

The reason why this is the preferable way to formulate it is because it fits with how the other transform entries looks like in the text books. It also illustrates the time delay (n-1) in the time series. Further, the other standard text book table entries would typically look like
Time domain: b^n
z-domain: z/(z-b)
and
Time domain: u[n]
z-domain: z/(z-1)
etc.

I attached a typical table I quickly found on internet to further illustrate my point. There are many more similar once that can be googled...
Hence, to not confuse the students it would be beneficial to use u[n] instead of δ[n] where possible.

So applying tables above to the example invztrans(2/(z-3),z,n) the HP prime should ideally output
2 * 3^(n-1)*u(n-1).

It would be great if all HP Prime z-transformation and inverse z-transformation output would follow the standard table text book look and notation. It would make it so much easier for the student.

Further, by convention we use the notation u[n] and δ[n] for the time discrete domain (δ[n] is the discrete Kronecker delta) rather than the Dirac delta term when calculating on paper. Dirac delta typically refers to δ(t) where t is in the continuous time domain (Real number domain) and the value of δ(t) when t=0 is actually infinity not 1. Note the use of [] for discrete domain and () for continuous (Real) domain when performing calculations on paper. On the Prime we could use δ(n) and u(n) for the discrete domain too as the notation is unambiguous in the z-transform context.