ROOT bug? HP 48S/48G  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: ROOT bug? HP 48S/48G (/thread226769.html) 
ROOT bug? HP 48S/48G  Eddie W. Shore  07112012 'X^3+5*X^22*X+7' 'X' 0 ROOT
But using the poly solver... [1,5,2,7] gives the correct answers: (approximately)
(.29141, 1.08117), (.29141, 1.08117), 5.58283
Re: ROOT bug? HP 48S/48G  Luiz C. Vieira (Brazil)  07112012 Hi.
I did not check it, but wouldn't it be a pole?
Re: ROOT bug? HP 48S/48G  Les Koller  07112012 If you read on the ROOT function of the advanced users manual, it shows you that you enter 1: function 2)variable to solve for 3) guess. The number returned is either the ROOT or the Local EXTREMA. There is a local minimum at x = .189....what your answer was. 0 (your guess) is closer to this value than the actual roots, that's why ROOT gave this answer for this specific guess.
Re: ROOT bug? HP 48S/48G  Eddie W. Shore  07112012 Quote:Good to know: thank you Les. I'll have to modify my program accordingly. Re: ROOT bug? HP 48S/48G  Les Koller  07112012 :)
Re: ROOT bug? HP 48S/48G  Gilles Carpentier  07132012 Same result with the 50G, using ROOT
Note that on the 50G, in approx mode : { 'X=(.291415279138,1.08116667823)' 'X=(.291415279138,1.08116667823)' 'X=(5.58283055828,0.)' } but is unable to find the exact roots I don't remember if SOLVEVX exists in 48 series [link:http://www.wolframalpha.com/input/?i=%27X^3%2B5*X^22*X%2B7%3D0%27]Wolfram math[/link]
Edited: 13 July 2012, 4:22 a.m.
Re: ROOT bug? HP 48S/48G  Les Koller  07132012 Yes, same result on 50G here too, which is what prompted me to go to the Advanced UM. :)
Re: ROOT bug? HP 48S/48G  Les Koller  07132012 Looks like, from the manual, the 48GX does not have solvevx.
Re: ROOT bug? HP 48S/48G  Eddie W. Shore  07132012 Quote:
I think SOLVEVX started with the HP 49G, not in the 48 series.
