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1. Go in CAS-Settings and deactivate "Exact"

2. Then In CAS-View type "solve(x³+x²=x,x)"

3. Look what happen.

Whats the matter ? (I have firmware 2013 8 13)

What do you get?

I get the 3 approx results wich seems OK

-1.6...., 0, 0.618...

/!\ TESTED on HP-PRIME VIRTUAL CALCULATOR (Is Not an Emulator)

[CAS MODE & EXACT MODE ON & HP-PRIME "EMULATOR"]

solve( x^3+x=x,x); [ENTER] =>

{((-(v¬(5))-1)/2),0,((v¬(5)-1)/2)} // OK

[CAS & EXACT MODE OFF] (APPROXIMATE)

solve( x^3+x²=x,x); [ENTER] => { -1.61803398875, 0, 0.61803398875} // OK

decoding the previous output

x=-1.61803398875 OR x=0 OR x= 0.61803398875

x^3+x²=x|x=-1.61803398875; [ENTER] =>

-1.61803398875 = -1.61803398875

EVAL(Ans); [ENTER] => 1 (TRUE)

x^3+x²=x|x=0; [ENTER] =>

0 = 0

EVAL(Ans); [ENTER] => 1 (TRUE)

but
eq0:= x^3+x=x;

solve(eq0, x); [ENTER] => returns a different answer every time you press enter

[enter] => ...

Another BUG with equations

solve( x²-10*x+y² = -8 AND x*y²+x-10*y = -8 , { x ,y } ); [ENTER]

=> { [ 1, 1 ], [ 2.19343941541,3.02046646812 ] }

decoding the previous output

x = 1 and y = 1 or x = 2.19343941541 and y = 3.02046646812

[CAS MODE & EXACT MODE ON]

purge(x,y);
x²-10*x+y² = -8 AND x*y²+x-10*y = -8; => 0 ????? BUG

x²-10*x+y² = -8 AND x*y²+x-10*y = -8 | x = 1,y = 1; ==> 1 (true)

Left part (step to step):

x²-10*x+y² = -8|x= 1; => y²-9 = -8

y²-9 = -8|y = 1; =>

-8 = -8 => true

Right part:

x*y²+x-10*y = -8 |x= 1; => y²-10*y+1 = -8

y²-10*y+1 = -8|y = 1; =>

-8 = -8 => true

true and true => true

but

x²-10*x+y² = -8 AND x*y²+x-10*y = -8 | x = 1; => 0 ???? BUG

=> OK => y²-9 = -8 AND y²-10*y+1 => y²-9 = -8 AND y²-10*y+1

Ans| y=1 => true

[CAS & EXACT MODE OFF] (APPROXIMATE)

purge(x,y);
x²-10*x+y² = -8 AND x*y²+x-10*y = -8; => x²-10*x+y² = -8 AND x*y²+x-10*y = -8; // OK


x²-10*x+y² = -8 AND x*y²+x-10*y = -8 | x = 1,y = 1 ==> 1 (true)

x:=1;
y:=1;

x²-10*x+y² = -8 AND x*y²+x-10*y = -8 => 1 (true)


Edited: 13 Oct 2013, 5:10 p.m.

Look at my video on 0:38. The calculator crash.

http://www.youtube.com/watch?v=YE1LiY6wOZo&feature=youtu.be

Sorry for the bad quality.

Is there anybody who can explain?

I cannot. I have never seen that before. Have you made any changes in the CAS settings screen? If so, please post them.

TW

Edited: 13 Oct 2013, 10:23 a.m.

yes, it is a bug.
I made another video:
http://youtu.be/I1CtxqS5W4g

Hi Tim,

please look also to the video of Edwin. He had the same problem.

I make no other changes in the CAS or general settings. I unpacked the calculator, go in CAS mode, change the exact-mode setting an try to solve the equation.

Tim, can you reproduce the bug of a real HP Prime with firmware 213 8 13 (5106)?

By the way: I have another HP Prime with firmware 2013 7 22. This calculator doesn't reboot but show only the answer {0.} in non-exact mode.

What is your firmware version?

Who is responsible for bugs? Is there an email-address for bugs? Or leaves hp ourselves?

Quote:
By the way: I have another HP Prime with firmware 2013 7 22. This calculator doesn't reboot but show only the answer {0.} in non-exact mode.


press enter again and get a second solution :)

eq0:= x^3+x=x; [ENTER]

solve(eq0, x); [ENTER] => returns a different answer every time you press enter

Who is responsible for bugs?

HP-PRIME TEAM

Is there an email-address for bugs? Or leaves hp ourselves?

required bug reporting page

+1 here. Reboot.

Quote:
press enter again and get a second solution :)

eq0:= x^3+x=x; [ENTER]

solve(eq0, x); [ENTER] => returns a different answer every time you press enter


The answers are somewhat close to 0. The solutions are on the order of 1E-9 or 1E-18. This behavior is at least consistent with the fact that the CAS is in non-exact mode, but certainly the solver could be more accurate.

That said, there is a setting in the CAS for epsilon. So users will likely expect that the solver be at least within epsilon. The default is 1E-12, so values on the order of 1E-9 are not sufficient.

Quote:
Who is responsible for bugs? Is there an email-address for bugs? Or leaves hp ourselves?

I am fairly positive that the folks at HP read the forums here, as well as other forums. I know that Tim, Cyrille, and Bernard in particular are active with the community, as well as many of the beta testers. You may be surprised that they frequent this board, adictoshp, cemetech, omnimaga, tiplanet, comp.sys.hp48 and many other forums.

One reasonable forum would be sufficient.

Do you know the reason of the mistake?

No, I've just reproduced the steps and the calculator did a reboot.

really phat!

Quote:
One reasonable forum would be sufficient.

My point was that users can choose to stick to any one forum they prefer. The folks working on the calculator do check all of them so that regardless of where you post, they will be read.

Edited: 14 Oct 2013, 10:48 p.m.