solution of equations with constraints HP 50g

[jam]

Greetings. I have a question. On the ti 89 calculator you could do, for example, 'solve(x^2 - 1 = 0)|x>0' to obtain the positive solution of an equation. Is it possible to do this with the hp48g or hp50g? How would it be done in agebraic mode and in rpn mode? I greatly appreciate your collaborations.

[Namir]

Supply a guess x> 0 and ignore any negative x results.

[jam]

(01-22-2024 11:43 AM)Namir Wrote:  Supply a guess x> 0 and ignore any negative x results.

Thanks for your answer. What you say is valid for a numerical solution, I am really interested in including the restriction, even with functions like SOLVEX in 50g, so an initial assumption would not work.

[roem76]

You could use ASSUME (and UNASSUME).

Example with ASSUME:
'X>0'
ASSUME
MSGBOX: Replacing strict with large inequality
'X>0' is replaced by 'X>=0'
'X^3-3=0'
SOLVEVX
'X=\v/3'

'X'
UNASSUME
SOLVEVX
{ 'X=-\v/3' 'X=\v/3' }

That was done with the HP50G in RPN-mode.

HTH
Roman

[jam]

(01-22-2024 12:32 PM)roem76 Wrote:  You could use ASSUME (and UNASSUME).

Example with ASSUME:
'X>0'
ASSUME
MSGBOX: Replacing strict with large inequality
'X>0' is replaced by 'X>=0'
'X^3-3=0'
SOLVEVX
'X=\v/3'

'X'
UNASSUME
SOLVEVX
{ 'X=-\v/3' 'X=\v/3' }

That was done with the HP50G in RPN-mode.

HTH
Roman

thanks, it worked perfect.