Symbolic solutions of an equation in HP 50g
04-09-2021, 08:41 PM (This post was last modified: 04-10-2021 04:10 PM by Gene.)
Post: #1
 Emibe Junior Member Posts: 5 Joined: Apr 2021
Symbolic solutions of an equation in HP 50g
Hi!, I have been searching a lot about this and I can´t solve my problem. The thing is that I want to solve an ecuation in function of others variables: for example ax+b=0---> x=-b/a. I tried to use the SOLVE function, but it only gives me the result for polynomical or simple ecuations. I wanted to solve for example : a*(x-(24a/24a+b)=c^2/(a(1-x)^2) (solve x in function of a b and c) but it doesn´t give me any result. I study engineering so the ecuations I use are normally not that easy to solve in function of other variables. Is there any solution to this problem? Is there any program that I can add to help with this?. Thanks and i hope that I explained my problem properly, inglish is not my first lenguaje!.
04-10-2021, 02:58 PM
Post: #2
 peacecalc Member Posts: 187 Joined: Dec 2013
RE: Symbolic solutions of an ecuation in HP 50g
Hello Emibe,

what is your calc, the answer differs with the machine you work with.
04-10-2021, 03:28 PM
Post: #3
 aurelio Senior Member Posts: 587 Joined: Dec 2013
RE: Symbolic solutions of an ecuation in HP 50g
(04-10-2021 02:58 PM)peacecalc Wrote:  Hello Emibe,

what is your calc, the answer differs with the machine you work with.
Hi, i think, from the post subject, it is a HP50g
04-10-2021, 03:31 PM
Post: #4
 Emibe Junior Member Posts: 5 Joined: Apr 2021
RE: Symbolic solutions of an ecuation in HP 50g
(04-10-2021 02:58 PM)peacecalc Wrote:  Hello Emibe,

what is your calc, the answer differs with the machine you work with.

It is a 50g
04-10-2021, 03:56 PM
Post: #5
 C.Ret Member Posts: 129 Joined: Dec 2013
RE: Symbolic solutions of an ecuation in HP 50g
(04-09-2021 08:41 PM)Emibe Wrote:  [...] I wanted to solve for example : a*(x-(24a/24a+b)=c^2/(a(1-x)^2) (solve x in function of a b and c) but it doesn´t give me any result. [...]

Sure, no serious HP calculator may give you a solution with an expression containing an odd number of parenthesis.

Also, I am no sure how to read this ONE « 24a/24a » ?
04-10-2021, 04:20 PM (This post was last modified: 04-10-2021 04:21 PM by Emibe.)
Post: #6
 Emibe Junior Member Posts: 5 Joined: Apr 2021
RE: Symbolic solutions of an equation in HP 50g
(04-10-2021 03:56 PM)C.Ret Wrote:
(04-09-2021 08:41 PM)Emibe Wrote:  [...] I wanted to solve for example : a*(x-(24a/24a+b)=c^2/(a(1-x)^2) (solve x in function of a b and c) but it doesn´t give me any result. [...]

Sure, no serious HP calculator may give you a solution with an expression containing an odd number of parenthesis.

Also, I am no sure how to read this ONE « 24a/24a » ?

I missed one parenthesis writing the post but that is not the subjet... I add an image of the expresion (it is only an example), but the thing is that the solver only give me solutions for simple ecuations that I can solve manually in a short time, but for ecuations more complicated that will take me more time to solve manually it gives me no solutions (that is one of the reasons I got this calculator, to save time).

Attached File(s) Thumbnail(s)

04-10-2021, 05:32 PM (This post was last modified: 04-10-2021 06:54 PM by Vtile.)
Post: #7
 Vtile Senior Member Posts: 404 Joined: Oct 2015
RE: Symbolic solutions of an equation in HP 50g
There is probably no simple general solution for that equation, while it does seems to be deceptively "simple". I did put it in my own HP50g just to see what it returns and the message is "lim error: Bad argument type", for solve for X (but I do not have any idea anymore which settings, as I'm using small userRPL program to prepare the equations for more favorable form and attached it to user key and then lost the actual program...) ... which to me means that the CAS-system tries to say that you are demanding too much.

You can try out some PC-based CAS systems, ie. Maple, XCAS etc., but I'm more than sure that that specific equation do not have a simple solvable solution considering how the solvable unknown X is distributed in the equation.

Engineering is fun isn't it.

PS. If you do give solve an list of {X A B C} to which solve for it do find solutions for B and C. The right side of the equations is where the complexities are.
Tried XCAS for just for interest. ...Damn I did drop the x from left side, it did work to be too easy...

Now with alost X, XCAS and HP50g do agree.

04-10-2021, 07:01 PM
Post: #8
 Emibe Junior Member Posts: 5 Joined: Apr 2021
RE: Symbolic solutions of an equation in HP 50g
(04-10-2021 05:32 PM)Vtile Wrote:  There is probably no simple general solution for that equation, while it does seems to be deceptively "simple". I did put it in my own HP50g just to see what it returns and the message is "lim error: Bad argument type", for solve for X (but I do not have any idea anymore which settings, as I'm using small userRPL program to prepare the equations for more favorable form and attached it to user key and then lost the actual program...) ... which to me means that the CAS-system tries to say that you are demanding too much.

You can try out some PC-based CAS systems, ie. Maple, XCAS etc., but I'm more than sure that that specific equation do not have a simple solvable solution considering how the solvable unknown X is distributed in the equation.

Engineering is fun isn't it.

PS. If you do give solve an list of {X A B C} to which solve for it do find solutions for B and C. The right side of the equations is where the complexities are.
Tried XCAS for just for interest. ...Damn I did drop the x from left side, it did work to be too easy...

Now with alost X, XCAS and HP50g do agree.
I see, maybe is what you say and the ecuation doesn´t have a simple solution. Thanks a lot!.
04-10-2021, 07:22 PM
Post: #9
 Vtile Senior Member Posts: 404 Joined: Oct 2015
RE: Symbolic solutions of an equation in HP 50g
(04-10-2021 07:01 PM)Emibe Wrote:
(04-10-2021 05:32 PM)Vtile Wrote:  There is probably no simple general solution for that equation, while it does seems to be deceptively "simple". I did put it in my own HP50g just to see what it returns and the message is "lim error: Bad argument type", for solve for X (but I do not have any idea anymore which settings, as I'm using small userRPL program to prepare the equations for more favorable form and attached it to user key and then lost the actual program...) ... which to me means that the CAS-system tries to say that you are demanding too much.

You can try out some PC-based CAS systems, ie. Maple, XCAS etc., but I'm more than sure that that specific equation do not have a simple solvable solution considering how the solvable unknown X is distributed in the equation.

Engineering is fun isn't it.

PS. If you do give solve an list of {X A B C} to which solve for it do find solutions for B and C. The right side of the equations is where the complexities are.
Tried XCAS for just for interest. ...Damn I did drop the x from left side, it did work to be too easy...

Now with alost X, XCAS and HP50g do agree.
I see, maybe is what you say and the ecuation doesn´t have a simple solution. Thanks a lot!.
https://www.wolframalpha.com/input/?i=so...x+symbolic
04-11-2021, 03:34 AM
Post: #10
 Emibe Junior Member Posts: 5 Joined: Apr 2021
RE: Symbolic solutions of an equation in HP 50g
(04-10-2021 07:22 PM)Vtile Wrote:
(04-10-2021 07:01 PM)Emibe Wrote:  I see, maybe is what you say and the ecuation doesn´t have a simple solution. Thanks a lot!.
https://www.wolframalpha.com/input/?i=so...x+symbolic

Oh, no wonder the calc doesn´t give me any solution xD... Thanks you !
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