HP49-HP50: list of var in an equation
10-02-2022, 10:19 PM (This post was last modified: 10-02-2022 10:29 PM by Gil.)
Post: #1
 Gil Senior Member Posts: 637 Joined: Oct 2019
HP49-HP50: list of var in an equation
I have, in the stack of the calculator, for instance the following equation (all the variables are with power of 1, but their coefficient being not necessarily integers):

'2.55*x1 + 19.07*b + 11*c1 - 50.333*d = k'.

My question: Is there a COMMAND or an easy way to get the list of the variables in the above equation (as the calculator detect those variables when executing STEQ 30 MENU)?

I checked, but could not solve this easy problem.

Just for infornation:
I try to copy a system of linear in equations from a book into the calculator.
I have to detect the variables and, afterwards, the coefficients of those variables (the latter question is easily solved by setting 1 variable to 1 and the remaining ones to 0).

Regards,
Gil
10-03-2022, 01:08 AM
Post: #2
 DavidM Senior Member Posts: 996 Joined: Dec 2013
RE: HP49-HP50: list of var in an equation
Try LNAME. It returns its result as an array, which can easily be converted to a list with AXL.

The Advanced Users Reference shows more details about LNAME and how it differs from LVAR, which provides a different take on the variables.
10-03-2022, 08:32 AM
Post: #3
 Gil Senior Member Posts: 637 Joined: Oct 2019
RE: HP49-HP50: list of var in an equation
Thanks, David, "your" LNAME command is the one I was looking for.

By the way, is there a built-in command or an easy way to get the coefficient of
Y='2.5*x + 7.5*b + 35* c'

apart evaluating Y for
(x=1, b and b = 0)
(b=0, x and c = 0)
(c=1, a and b = 0)?

Regards,
Gil
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