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About the way HP Prime CAS handles complex square roots - Printable Version

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About the way HP Prime CAS handles complex square roots - dah145 - 07-04-2021 01:46 AM

Recently it has come to my attention the unorthodox way the HP prime handles complex square roots compared to other CAS systems, to demonstrate what I'm referring to here's an example for the expansion of the expression sqrt(x+i*y) on the TI-89 with rectangular complex mode:

[Image: Screenshot-2021-07-03-173534.png]

[Image: Screenshot-2021-07-03-174412.png]

Results can also be obtained conveniently in polar form changing an intuitive setting in the mode window.

Numerical values are also handled in Exact mode without issue on the TI-89:

[Image: Screenshot-2021-07-03-181817.png]

Ironically enough, the HP 50G also seems to handle these expressions more gracefully than its spiritual successor:

[Image: Screenshot-2021-07-03-182431.png]

And being capable of numerical exact values for these expressions as you would expect:

[Image: Screenshot-2021-07-03-183413.png]

Meanwhile in the HP Prime, a simplify(sqrt(x+i*y)) gives a series of warnings:

[Image: Screenshot-2021-07-03-182705.png]

And outputs an useless gigantic expression for which its simplification is as useless and takes a significant amount of time:

[Image: Screenshot-2021-07-03-183014.png]

Futhermore, perhaps one the most lacking things in the HP Prime, it is impossible to this day to obtain an exact numerical result for these expressions as they are all automatically approximated:

[Image: Screenshot-2021-07-03-183656.png]

[Image: Screenshot-2021-07-03-184439.png]

I think it is valid to expect the HP Prime to be able to manipulate this expressions in exact mode, seeing as even a Casio Algebra FX 2.0 is capable of doing so...
Is there any chance this will get updated in a future OS version?

This was briefly discussed in a past thread here:
https://www.hpmuseum.org/forum/thread-4647.html


RE: About the way HP Prime CAS handles complex square roots - roadrunner - 07-04-2021 01:32 PM

There is a lot of discussion on that vary topic through out this forum, here is another thread:

https://www.hpmuseum.org/forum/thread-6928.html?highlight=rootroot

-road


RE: About the way HP Prime CAS handles complex square roots - dah145 - 07-05-2021 11:07 PM

(07-04-2021 01:32 PM)roadrunner Wrote:  There is a lot of discussion on that vary topic through out this forum, here is another thread:

https://www.hpmuseum.org/forum/thread-6928.html?highlight=rootroot

-road

I see, this definitely merits discussion, as it's a CAS calculator not behaving as one.