HP 50g Error and user Manual Error
10-29-2015, 10:00 PM
Post: #1
 lrdheat Senior Member Posts: 857 Joined: Feb 2014
HP 50g Error and user Manual Error
Just noticed an error on page 6-10 of the user manual that came with my HP 50g years ago...

In the explanation of the SOLVE environment, they use the equation e^x - sin(pi*x/3)=0.

They show a solution (a root) of ~4.5E-02. This is actually an extremum, (f(x)=~.9989) which the Prime correctly shows in it's solve app. I confirmed that the HP 50g handheld produces this error. The HP 50g user manual then shows another solution (of infinitely many) that can be found by putting a guess of -3 into the field for "X". This correctly produces ~-3.045.
10-29-2015, 11:54 PM (This post was last modified: 10-29-2015 11:56 PM by Joe Horn.)
Post: #2
 Joe Horn Senior Member Posts: 2,002 Joined: Dec 2013
RE: HP 50g Error and user Manual Error
(10-29-2015 10:00 PM)lrdheat Wrote:  Just noticed an error on page 6-10 of the user manual that came with my HP 50g years ago...

In the explanation of the SOLVE environment, they use the equation e^x - sin(pi*x/3)=0.

They show a solution (a root) of ~4.5E-02. This is actually an extremum, (f(x)=~.9989) which the Prime correctly shows in it's solve app. I confirmed that the HP 50g handheld produces this error. ...

Yes, the manual is in error in stating that it is a solution, but no, the 50g itself is not in error, because if you press the INFO menu key, you'll see that the returned value is an "Extremum". After pressing SOLVE on the 50g, you should always press INFO.

<0|ɸ|0>
-Joe-
10-29-2015, 11:58 PM (This post was last modified: 10-30-2015 12:29 AM by Vtile.)
Post: #3
 Vtile Senior Member Posts: 406 Joined: Oct 2015
RE: HP 50g Error and user Manual Error
My HP50g gives "Solve error: Not reducible to a rational expression" when trying to solve X with random flags with "SOLVE" (should it be renamed to ErGen /sarcasm) command. :&

In comparison CASIO- ClassPad 2 gives with its generic solve command without quesses in Real and Precise (Non Aprox) or decimal mode (aprox) solutions for X:
{x=-30, x=-27, x=-24, x=-21, x=-17,99999, x=-11,99999413, x=-9,000117834, x=-5,997, x=-3,0454479} With warning that there might be more solutions.

Without any fanboyism added to direction or another, I start to feel my voyage (costs 380€ so far) to find a new calculator for next odd tens of years isn't over.. saddens me since HP50g is a gem except that the CAS side seems to be a badly crippled in usability standpoint which is pretty severe foult looked a the philosophical standpoint of the reason of calculator exist at all. Next try will be Prime, hopefully it is not a heap of **rd. The 35S and 50g do not give only sweet taste to my mouth. This last paragraph is for those forum gent who are HP insiders.
10-30-2015, 01:45 AM
Post: #4
 lrdheat Senior Member Posts: 857 Joined: Feb 2014
RE: HP 50g Error and user Manual Error
Perhaps this should be in the Prime thread, but I do notice, that while in the graphing app on the Prime, if I pick a point on the graph near the extremum in question (X~.045), and choose "root", the curser goes to this point. Why?

Again, in the numeric solve app, this point correctly throws an error, stating that it has come up with an extremum.
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