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Use of HP27s/19b and Plus42 solver - Printable Version

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Use of HP27s/19b and Plus42 solver - Marco Polo - 08-14-2023 01:49 PM

I am very used to HP48/50 Multiple Equation Solver (MES) and i am managing to start using Plus42 even if it doesn't have something similar.
Just to start with something easy, i am playing with Ideal Gas Law.
In HP50 i have the following equations
Code:
{ 
'P*V=n*CONST(R)*UBASE(T)'
'm=n*MW'
}
This simple system considers UOM and allows the solution in case only moles or mass are required/available.
In Plus42 i tried to use the L function to reproduce MES behaviour
Code:
'P*V-L(n:m/MW)*8.31451_"J/gmol/K"*UBASE(T)*UVAL(n/n)'
but i cannot solve for 'n' (other variables work ok)

Am i doing something wrong or there is no way to get the score?

Thank you

RE: Use of HP27s/19b and Plus42 solver - Eddie W. Shore - 08-15-2023 03:27 AM

I'm at a loss too.

However, if units are used for one variables, I think units need to be used for all the variables and constants.

RE: Use of HP27s/19b and Plus42 solver - Marco Polo - 08-15-2023 06:59 AM

(08-15-2023 03:27 AM)Eddie W. Shore Wrote:  I'm at a loss too.

However, if units are used for one variables, I think units need to be used for all the variables and constants.
Units are used for all variables and work properly.
I can solve the equation for every variable, except n.
Indeed, I can only see the value of n after equation solution

RE: Use of HP27s/19b and Plus42 solver - Vincent Weber - 08-16-2023 10:38 AM

You need to use the S() [solving] function:

IF(S(n) :equation 2: equation 1)

Then giving m and MW you can solve for n, then solve for other variables in the first equation.

RE: Use of HP27s/19b and Plus42 solver - Marco Polo - 08-16-2023 03:43 PM

(08-16-2023 10:38 AM)Vincent Weber Wrote:  You need to use the S() [solving] function:

IF(S(n) :equation 2: equation 1)

Then giving m and MW you can solve for n, then solve for other variables in the first equation.
Great, it is a very nice trick.
I missed the information.

Thank you very much!