Why won't the prime graph correctly?

[Gilles]

(05-23-2019 03:42 PM)Nigel (UK) Wrote:  

(05-23-2019 09:14 AM)Aries Wrote:  Quite the contrary, teachers know very well what they are teaching, calculators are stupid and/or badly programmed
Best,

Aries

I suppose different people have different opinions. Here are what the four calculators with me at school (I teach Physics) today say:

• DM42: doing 1 +/- ENTER 3 1/x y^x gives the first complex cube root of -1, rather than -1.
• WP34S: doing 1 +/- ENTER 3 1/x y^x gives DOMAIN ERROR.
• Casio Classwiz fx-85GTX: doing (-1)^(1/3) gives -1.
• HP Prime: (-1)^(1/3) gives an error in Home mode (only integral powers of negative numbers allowed) and a complex result in CAS mode.
  

I like all of these calculators and I think they behave well.

Nigel (UK)

WolframAlpha gives the same complex result as does the HP50g, newRPL, HPPrime (in home mode,set allow complex number). There is a bug in the NSpire here