Re: HP Prime Bug
Message #15 Posted by CompSystems on 12 Oct 2013, 4:29 p.m.,
in response to message #1 by bluesun08
/!\ 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.
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