Equation can't solve with 2.15 but 2.10 can

Equation can't solve with 2.15 but 2.10 can - Printable Version

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Equation can't solve with 2.15 but 2.10 can - BINUBALL - 03-18-2021 08:03 AM

I have the equation that cannot solve in 50g with rom version 2.15.
x^2+x*y=10 and y+3*x*y^2=57.
In rom 2.15 When I tried solve this equation. It gives "Unable to factor" in exact mode, "Not exact system" in approx mode. You might think it's a normal case up to here, but In EMU48 with rom 2.10 CAN SOLVE IT!. It demands change mode to approx. and gives answer.
Why 50g with rom version 2.15 cannot solve it?

RE: Eqaution can't solve with 2.15 but 2.10 can - peacecalc - 03-18-2021 11:33 AM

Hello PINUBALL,

try:

stack (3): [ 'x^2+x*y=10' 'y+3*x*y^2=57']
stack (2): ['X' 'Y']
stack (1): [1 1] initial guess

and use command MSLV, you get [2.000 3.000].

RE: Eqaution can't solve with 2.15 but 2.10 can - BINUBALL - 03-18-2021 11:46 PM

(03-18-2021 11:33 AM)peacecalc Wrote: Hello PINUBALL,

try:

stack (3): [ 'x^2+x*y=10' 'y+3*x*y^2=57']
stack (2): ['X' 'Y']
stack (1): [1 1] initial guess

and use command MSLV, you get [2.000 3.000].

I know that method, but I want to get all 4 roots. Because EMU48 gives 4 roots.

RE: Eqaution can't solve with 2.15 but 2.10 can - franz.b - 03-19-2021 11:58 PM

what is the exact procedure you use to solve? I have a 50g with firmware 2.15 and one with 2.08. If you want I can do some tests.

RE: Eqaution can't solve with 2.15 but 2.10 can - BINUBALL - 03-20-2021 02:10 AM

(03-19-2021 11:58 PM)franz.b Wrote: what is the exact procedure you use to solve? I have a 50g with firmware 2.15 and one with 2.08. If you want I can do some tests.

stack (2): [ 'x^2+x*y=10' 'y+3*x*y^2=57']
stack (1): ['X' 'Y']
Mode is exact, complex. Thus Header will be C=. And execute SOLVE. In my emu48, It ask change mode to approx and gives four answer. 2.15 return Unable to factor.
Here is picture of my emu48 gives four roots.
[attachment=9250]

RE: Equation can't solve with 2.15 but 2.10 can - franz.b - 03-20-2021 10:05 AM

with both calculators the result is "Unable to factor".
For example, are you sure that all other system flags are set the same way? [Image: 27.gif]

RE: Equation can't solve with 2.15 but 2.10 can - BINUBALL - 03-20-2021 10:58 AM

(03-20-2021 10:05 AM)franz.b Wrote: with both calculators the result is "Unable to factor".
For example, are you sure that all other system flags are set the same way?

I moved EMU48's flag setting to real 50G and that eq gives four roots. After flag compare, I figured it out. Answer is -109 SF. If -109 is set, numeric factorization is allowed.
I think after SF 109, most "Unable to factor" problem can solved.

RE: Equation can't solve with 2.15 but 2.10 can - peacecalc - 03-20-2021 11:06 AM

Hello all,

I tried it, too. Yes, with flap 109 it works! Again, learned something new about that crazy machine, called hp 50g! Thank you all!

RE: Equation can't solve with 2.15 but 2.10 can - franz.b - 03-20-2021 12:56 PM

With the flag setting it works on both my versions, 2.08 and 2.15.