Problem between CAS mode and HOME mode, VARS A,... Z

[compsystems]

Hello

There is a serious problem between CAS mode and HOME mode, HOME mode stores the variables A, ...Z which are common operation variables of an algebraic expression. This can be solved in HOME mode, using instead of A, ...Z, the same letters but with subgion A_, ...Z_, thus freeing the letters A, ...Z, to be used to operate symbolic expressions.

In the expression history, the letters A_, ...Z_ would appear as bold letters.

Now in HOME mode when typing the letter A, it places A_, while in CAS only A

Good idea?

[Albert Chan]

(11-08-2024 03:49 PM)compsystems Wrote:  Now in HOME mode when typing the letter A, it places A_, while in CAS only A

If A in Cas side really mean Cas side A, this may break all previous code.

I had suggested similar idea, to separate the names for both sides.
My implementation idea is different, keeping HOME as is, just change CAS side

AA → A, to save time to hunt for underscore key.

CAS: overriding HOME variables, bug or feature? (for me, a feature!)

[compsystems]

but the internal code would show expressions with double letters, which look very bad, whereas with an underscore they don't look so bad.

Code:

A_ = 2 * pi * R_^2

=>

A = 2 * pi * R^2

whereas

Code:

AA = 2 * pi * RR^2

[Albert Chan]

Perhaps I should elaborate.

Typed: AA = 2 * pi * RR^2
Shown: A = 2 * pi * R^2

You'd never see AA, RR. Its all internal.
Bolded reminded us that this is not HOME variables.

A_,R_ work too. I am not picky with how internally it get stored.

[compsystems]

when designing the manuals I think students might interpret AA as A*A , it is better with a subscript.

Hopefully the Hp-prime group will take this possible solution into account.


R_:=3; [ENTER]
R:=3
A_ := 2 * pi * R_^2; [ENTER]
A = 2 * pi * R^2
56.5486677646

In this way, the letters A and B are free for symbolic manipulation.
R:=ABS(A+B*I) [ENTER] sqrt(A^2+B^2)


Now, why not always write in lower case in CAS, not because some expressions may have two variables with the same symbol A and a and others, depending on the context, are written in upper case and others in lower case.