Continuous Fibonacci Parametric Plot

[Rick314]

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?


   

   

   

[victorvbc]

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)

   

[Rick314]

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.

[jte]

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")

   

(I made two copies of the function pair and restricted one to negative T, the other to non-negative T.)