Bug in solve app?

[MrMcChicken]

Hello, somehow I think I found a bug in the solve app.
If I enter two equations:
-5.5=A*-15.5+B*-50.5
-14.1=A*-39.5+B*-4.5

The shown result is:
A: 0.357...
B: -6.75...

But this is not correct. If I enter the equations in the linear solver app
the results are:
A:0.35...
B:-0.000675...

Those are correct. Is there something wrong or have I messed up some settings?

[DrD]

In the Solver App, does the result shown for B happen to be −6.80ᴇ−4 as the displayed value? Your ellipsis cuts off any possibility of the power of 10 in the result.

In matrix form, if

M0:=[[−15.5,−50.5,−5.5],[−39.5,−4.5,−14.1]]

And

M1:=RREF(M0);

Then
M1(2,3) == B == −6.80ᴇ−4 == the result shown in Solver App

-Dale-

[MrMcChicken]

I have uploaded two pictures to show the problem.

The result of the solver app:


The linear solver app:


The second one should be correct.

[Dirk.nl]

Confirmed!

[DrD]

I retried the Solve App using the information as provided:

[Symb]
E1: -5.5=A*-15.5+B*-50.5
E2: -14.1=A*-39.5+B*-4.5

[Num] [Solve]
A: 0.357038961039
B: −6.75324675325ᴇ−4

(The Solve App worked in this case on both the VC and HC).

Do you get the same error on the emulator? (Perhaps, Tim may be able to offer some insight on this).

-Dale-

[MrMcChicken]

I don't have installed the latest version. I will install it later and have a look.
Somehow I get strange results in general.
Another example:

3376*A+225*B+15*C+D=0
125*A+25*B+5*C+D=5
675*A+30*B+C=0
30*A+2*B=0

The results I get are: A=0 B=0 C=0 D=8

[slawek39]

I have this same problem on real calculator. FW10077
But Android emulator gives correct result.

Slawek39

[DrD]

(05-07-2016 11:46 AM)MrMcChicken Wrote:  I don't have installed the latest version. I will install it later and have a look.
Somehow I get strange results in general.
Another example:

3376*A+225*B+15*C+D=0
125*A+25*B+5*C+D=5
675*A+30*B+C=0
30*A+2*B=0

The results I get are: A=0 B=0 C=0 D=8

For your example, I get:

   

[Dirk.nl]

Hi all,
I have the same results as MrMcChicken and Slawek39,
Dale, can you, maybe, explain that it works correctly on your calculator?
Have you also FW10077?
Have you changed some settings?
Tim or Cyrille, can you help us, please? (Thanks)

[factor]

My emulator result:
   
   

[Helge Gabert]

I've long since given up on the solve app (can't even solve a simple two-liner like 5*A+7*B=39 and -2*A+B=-8 - - hitting solve soft key has no effect, regardless of starting values). FW 10077, physical Prime.

Just use RREF for linear equations, and fsolve for non-linear ones (which also allows for complex solutions).

[informach]

Hi!:

In my emulator of Android with version 8151, have the results, indicated in the attached files.

Kind Regards.
informach.

[slawek39]

(05-07-2016 01:16 PM)slawek39 Wrote:  I have this same problem on real calculator. FW10077
But Android emulator gives correct result.

Slawek39

This message applies to the first post with B=-6.75 (2 equations)
The problem with 5 equations is corect on my Calculator (Hardware Version A)

slawek39

[informach]

Hi!:

For the examples, of ... MrMcChicken

I checked, in my HP PRIME Calculator, with ...
Software Version 2016 04 14 (10077)
Hardware Version: A
CAS Version 1.1.2-11
Operating System : V0.042.570

The results have error's, in example E1 and E2, with Exact Mode and Standard 12 digits ....

E1: 3,376*A+225*B+15*C+D=0 --> 2.5012506253
E2: 125*A+25*B+5*C+D=5 --> -37518759379

The correct results, they should be ...
E1: 0.0025012506
E2: -0.037518759

Kind Regards.
informach.

[German90]

I have the 14/04/16 firmware and I'm having the exact problem. Maybe it's a bug.

[informach]

Hi!, German90:

Yes, it's a bug, of new version.

IMHO, what Tim Wessman, he must take action, for correct it, in the next version.

Kind Regard and very happy weekend !.
informach.
********************************************************************************​********************

(05-07-2016 11:31 PM)German90 Wrote:  I have the 14/04/16 firmware and I'm having the exact problem. Maybe it's a bug.

[Marcel]

Hi!

Same for me... It is difficult to trust the Prime.. I don't no what to say.

Just a question:

For testing the Prime, HP use

A. a HP calculator (48, 49 or 50g)
B. Mathematica
C. TI-Nspire CX CAS
D. CASIO Calculator
E. No test, because HP is the best!

The answer is: ___



Marcel

[informach]

Hi!, Marcel:

This problem occurs, with the new version 10077. If you have the version 8151, will not have, this problem; however, as is HP Invent and certainly, in the next version, they will solve, as other bugs. There is a very good development team, this gem. This is similar, to the disadvantages, of the Windows 10.

Kind Regards.
informach.

[Marcel]

Hi informach!
I know they will correct it.. This is only a bad joke...
I only want to trust the Prime like my 48, 49 or Nspire...
Thank you
Marcel.

[informach]

Hi!, Marcel:

That's, for sure. I come from, far away with HP (HP67/41CV/28C/75C/48G+/49G/50G/HP PRIME) and no exist one, can replace the HP's. Imagine, what calculators that NASA used its shuttle flights (HP35/HP41CX/HP48GX/HP42S) and now provides, exclusively to NASA, all equipment (can you expect more?).

Kind Regards.
informach.