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10-25-2018, 05:59 AM (This post was last modified: 10-25-2018 06:53 AM by Anders.)
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RE: Change displayed form?
(10-25-2018 04:17 AM)rushfan Wrote:  
(10-25-2018 02:56 AM)Anders Wrote:  Thanks. I get that, but that was not really my point (there were many). To know that you need to apply exp2trig you need to know the answer (which you typically do not until; you have tried ilaplace() first).

My view was that the average EE (or any engineering doing differential equations) undergrad student pov would not immediately know this when they see a bunch of e ^ -ix....., but that a student would reasonably expect the ilaplace() to present the familiar mapping back to the time domain.
You now, like the classic laplace tables the professor gives the students at the beginning a circuit class. Just look at Wikipedia for instance Laplace transform
same goes for z transforms dealing with the discrete time domain:
Hugely important also in comp sci.

What that student need to know is that "i" should not be checked in CAS setting for the mapping to work as expected.

In some ways it is actually good that ilaplace can present both the complex form and the non-complex. It makes it more flexible if you want to do more advance stuff but, maybe by default, ilaplace() should always show the non-complex form (regardless of "i" CAS setting) and have a parameter complex on/off to explicitly tell CAS to show complex form. ilaplace(expression of parameter 1, [param 1 (i.e. t)], [param 2 (i.e. s)], [normalized flag Y/N: default Y], [complex Y/N: default N])

Just a thought. I think HP/Parisse, would get fewer questions and the students would better intuitive and immediate use of the HP Prime.

I would certainly have loved to have had and HP Prime with that capability in grad school. It would save so much time and avoid errors in the mapping back and forth the between time and frequency domain of complex circuits analysis.

Anyway, the other errors I mentioned above is still a problem.

Having the answers displayed in complex exponential form is essential in a signals and systems course, on an EET (Electronics Engineering) graduation. I learned how to do the transforms by hand in that course before being asked to do them "by table". And in this case, the default settings present the familiar answer (in terms of the functions) as it should, so not an issue IMHO.

And yes, there are a ton of not intuitive and not sufficiently detailed and exemplified things in the cas documentation. Recently, it took me a forum post to figure out that the function "normal()" exists and does what I needed.

Yes, so I think we agree then.... CAS Documentation remains a challenge.

As there are several typs of uses where you absolutely want the complex exponential form (e.g. fundamental to the detail components R,C,L in circuits) and looking at the systems level (time discrete/ continuous systems and control theory) it is beneficial to work in the z and s standard form. Also, it is also beneficial to manipulate and transform entire systems (formulated in s and z) in vector and matrix form back and forth...

Both "complex" and s,z form as well as normalized/default form are needed as output AND need to be documented.

Ideally the laplace() and ilapalce() (as well as ztrans and invztans) needs to have parameters allowing the user to specify what output form he/she wants rather than changing a CAS system setting.

This would allow the user to move between the time domain and frequency domain using different forms efficiently without going in and changing CAS settings back and forth.

However, the issues with the virtual Prime is still a problem. At least it does not work for me even with purge(s,x,t)...
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Messages In This Thread
Change displayed form? - DrD - 10-20-2018, 09:52 AM
RE: Change displayed form? - Albert Chan - 10-20-2018, 12:33 PM
RE: Change displayed form? - DrD - 10-20-2018, 05:20 PM
RE: Change displayed form? - Anders - 10-24-2018, 02:18 AM
RE: Change displayed form? - rushfan - 10-25-2018, 02:01 AM
RE: Change displayed form? - Anders - 10-25-2018, 02:56 AM
RE: Change displayed form? - rushfan - 10-25-2018, 04:17 AM
RE: Change displayed form? - Anders - 10-25-2018 05:59 AM
RE: Change displayed form? - Anders - 10-24-2018, 03:42 AM
RE: Change displayed form? - parisse - 10-24-2018, 05:27 AM
RE: Change displayed form? - Anders - 10-24-2018, 03:36 PM

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