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+--- Thread: Continuous Fibonacci Parametric Plot (/thread-14808.html)
Continuous Fibonacci Parametric Plot - Rick314 - 04-08-2020 12:36 AM
I am using the HP Prime Virtual Calculator v2.1.14425 (2020 1 16) Parametric App to attempt to plot the continuous Fibonacci parametric function (image 1). It has a complex result and I am trying to plot the RE and IM parts. As T goes from -9 to 9 the resulting complex-valued result should look like the last image below, produced with Derive for Windows version 5.06. Instead, for example with Trace on and T = 1.5, I get the "(NaN, NaN)" result shown. But it is close -- Jump to T = 6 and the correct real value (8,0) is shown (the 6th Fibonacci sum 1 1 2 3 5 *8*). Why isn't the desired plot shown by HP Prime?
[attachment=8311]
[attachment=8312]
[attachment=8313]
RE: Continuous Fibonacci Parametric Plot - victorvbc - 04-08-2020 01:04 AM
If you get the real and imaginary expressions from CAS and copy those to the parametric app, you get the desired result.
Do:
X1:=unnaply(RE(f(x)),x)
Y1:=unnaply(IM(f(x)),x)
[attachment=8314]
RE: Continuous Fibonacci Parametric Plot - Rick314 - 04-08-2020 01:28 AM
Thanks much and now I have the desired graph looking like your provided image. But when I turn on Trace and vary T, I still get "(NaN,NaN)" at all non-integer T values, unlike your display for T=-5.993 that shows the correct values. (I am new to HP Prime and suspect some trivial configuration setting?)
Edit: No need to reply. It all works if I delete the incorrect version I originally posted.
RE: Continuous Fibonacci Parametric Plot - jte - 08-10-2021 11:57 PM
When I tried with the current version (2.1.14592 (2021 06 09)), I did manage to get a plot to come up after checking (enabling) the Complex setting in Home Settings. ("Allow complex output from real input")
[attachment=9726]
(I made two copies of the function pair and restricted one to negative T, the other to non-negative T.)