Hello!
I'm trying to create an array of simultaneous equations, but the ->ARRY function doesn't seem to be working properly. Can anyone see what I'm doing wrong?
The stack contains:
4: 'X+Y=30'
3: 'Y=Z+2'
2: 'X=14+Z'
1: 3
...and when I issue the ->ARRY function, I get:
->ARRY Error:
Bad Argument Type
I'm totally confused, since the MSLV function REQUIRES an array of the equations!
Hi.
The ~>ARRY command accepts only numerical entries in the HP48 series. IIRC, the HP49 accepts single variables, but I cannot tell you for sure.
You should try:
[1 1 0]to assemble the coefficient matrix, then
[0 1 -1]
[1 0 -1]
3
[30]to assemble the constants vector. Please, check for possible syntax relevance, I am writing by heart.
[2]
[14]
3
One question: the MSLV you mention is the MSOLVR? If so, it demands a list of equations (or expressions, I do not recall correctly) stored in the EQ variable.
Cheers.
Luiz (Brazil)
Edited: 16 Apr 2012, 12:40 p.m.
Looks correct ... This must works
Can you verify that your equations are TYPE 9. ?
Edit : oups... My reponse is for 49-50 (it works perfectly), I do not know about 48.
Edited: 16 Apr 2012, 12:39 p.m.
Thanks Luiz! That does appear to be the problem - that strings can't be arguments for ->ARRY. :(
Also, MSLV is the name of the function I wrote about. If you have the 864 page 48gii user's guide it is described on page 7-4.
You might want to try this program. If the stack contains
4: 'X+Y=30'3: 'Y=Z+2'
2: 'X=14+Z'
1: {X Y Z}
press SYS (F2) to obtain
X (F1) --> 21.Y (F2) --> 9.
Z (F3) --> 7.
MAT (F4) --> |1. 1. 0. 30. |
|0. 1. -1. 2. |
|1. 0. -1. 14.|EQS (F5) --> { 'X+Y=30' 'Y=Z+2' 'X=14+Z' }
Thank you Gerson! :)
With 49/50 you can solve this systems in 2 ways :
1/Use LINSOLVE with vectors
['X+Y=30' 'Y=Z+2' 'X=14+Z'] @ you can use Matrix and equation writer for this
[ 'X' 'Y' 'Z' ] @ It must be _vectors_ and not matrices ( VEC must be check in matrix writer : VEC#)
LINSOLVE @ Shift S.SLV LINSO->
[ X=21 Y=9 Z=7 ]
This works in symbolic way even with more than 3 unknows for 3 equations
I have forgot that this don't work on 48
|x| |x| -1
2/ Use matrices : M.|y|=V => |y| = M .V
|z| |z|[[1 1 0] @ With matrix writer type
[0 1 -1] @ 1 1 0 ENTER RShift <- v
[1 0 -1]] @ 0 1 -1 1 0 -1 ENTER[[30][2][14]] @ With matrix writer 30 ENTER 2 14 ENTER
@ or [] [] 30 -> 2 14 ENTER
SWAP /->
| 21 |
| 9 |
| 7 |
This works in numeric and symbolic with HP49/50
Only in numeric with my old 48SX (it works here for exemple)
Edited: 16 Apr 2012, 5:12 p.m.
You're right! On the HP-49/50g LINSOLVE is a better option, as I've just checked. On the HP-48, AFAIK, there's no built-in command to do it symbolically though.
Nice solution!! Curious how you invert that matrix?
Quote:
...
In fact that is a 4 x 10 matrix ;)
Edited: 16 Apr 2012, 11:40 p.m.
You can't because it's not a square matrix :D
Edited: 17 Apr 2012, 7:01 a.m.
Quote:
Curious how you invert that matrix?
How about this (especially for Joerg!)
This is a unique system: has more solutions in itself than the ones needed to solve it!
Quote:
In fact that is a 4 x 10 matrix ;)
not for the TI fans :)
