[HP Prime] "Error while checking exact value with approximate value, returning both!"  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: [HP Prime] "Error while checking exact value with approximate value, returning both!" (/thread257700.html) 
[HP Prime] "Error while checking exact value with approximate value, returning both!"  Chris Pem10  12052013 The output of this integral would be confusing to a student: Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Tim Wessman  12052013 The issue is that there really is not great support for the nthroot form due to personal preferences of the CAS author. Use ^1/3 and it works fine.
TW
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Chris Pem10  12052013 In fact, the CAS's nthroot errors are somewhat predictable:
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Alberto Candel  12052013 The conventions for nth root and 1/n power in xcas are explained in pages 64 and 65 of
They are different from those in Mathematica(TM).
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Chris Pem10  12052013 Thank you for the reference; I'm looking into it :)
In my opinion, the software author's method of interpreting powers and nth roots "taints" the CAS and propigates errors throughout the system. Or I'm just not understanding something here?
Edited: 5 Dec 2013, 1:58 p.m.
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Chris Pem10  12052013 Actually, both limits produce the correct result in XCAS in Linux: Edited: 5 Dec 2013, 2:22 p.m.
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Alberto Candel  12052013 It looks like the xcas in the Prime is not up to the official xcas. Besides the Prime cas seems to have changed between updates. Here is what I obtain with an older emulator (the one I have running in Linux under wine)
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Chris Pem10  12052013 I can confirm that both limits return the correct result in Home view (used capital X as the variable).
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Alberto Candel  12052013 This is what I get at Home with the above emulator Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Mark Hardman  12052013 You are a release behind. As reported below, this is working correctly in the new release.
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Mark Hardman  12052013 Chris, In your first example you are taking the limit as b goes to 0 of (1 + b). This result is 1. You are then taking that result to the power of 1/b. This gives the correct result of 1 (1^n=1).
You need to add an extra pair of parenthesis starting at the limit and closing at the end of the expression. This gives the correct result of e. limit(1+b,b,0)^(1/b) = 1
Edited: 5 Dec 2013, 5:41 p.m.
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Chris Pem10  12052013 Yes. You are correct ! Obviously PEBKAC in this case.
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  Tim Wessman  12052013 Well, I think this needs work on our end to clarify what is happening. It is an easy mistake to make since there are times it can not be clear to what the function is being applied. I've flagged another mark on that item to float it up higher in the queue.
TW
Re: [HP Prime] "Error while checking exact value with approximate value, returning both!"  parisse  12062013 There is an error in the antiderivative of NTHROOT/surd for linear argument explaining the factor 2 errot, I'll fix that. In the meantime use fractional powers...
