Solution to the problem of preassigned variables to 0

10252018, 06:20 PM
(This post was last modified: 11042018 08:20 PM by compsystems.)
Post: #1




Solution to the problem of preassigned variables to 0
Solution to the problem of preassigned variables A, ... Z, Z0, ..., Z9, F0, F9, ..., V0, ..., V9 etc. to 0
Hello HPPrimeTEAM and users, one of the difficulties of the HPPrime calculator, is that there is no integration between CAS and NUM/HOME mode and especially in applications, since they are using predefined variables, in addition students have problems in differentiating X with x, since X is predefined to zero, they always call me, I do not get what I expected, another student asks me if X is set to zero, because when creating the function does not evaluate it. There is no consistency in the hpprime system X [enter] returns 0 F1(X) := 8 * X  5 This should return 5 solve((right(F1)) = 0,X,'=') returns [] // synonym of no solution. x:=0 [enter] returns 0 assume(x,symbol) // Remove the value of 0, changing the data type to symbolic x [enter] returns x F10(x) := 8 * x  5 One solution that I propose is that the variables are predefined with 'noValue' instead of zero, in this way X + 3 [enter] in NUM/Home mode returns "Syntax error" // ok, because it can not evaluate X, X has symbolic value X + 3 [enter] in CAS mode returns X + 3 // ok because X is considered a symbolic variable then: X:=5 X + 3 [enter] in NUM/Home mode returns 8 X + 3 [enter] in CAS mode returns 8 restore(X) [enter] returns 'noValue' X + 3 [enter] in NUM/Home mode returns "Syntax error" // ok What do you think of this idea? Another Case: V1(X,Y) := (X²/3  Y²/5 = 1); [enter] returns (X,Y)>(((X^2/3)(Y^2/5))==1) // error (X,Y)>((X^2/3)(Y^2/5))=1 // ok right(V1) [Enter] returns 0 // (0 synonymous of false), error because although ((X^2/3)(Y^2/5) == 1 is false, this should not be compared, it must be interpreted as equation (X,Y) > ((X^2/3)(Y^2/5))=1 I do not use x in lowercase because the internal user variable V1 requires it [SYMB KEY], I also want to perform analytical [CAS], graphical [PLOT KEY] and numeric analyzes [NUM KEY] using the same definition. Thanks LO SUFICIENTEMENTE BUENO ES ENEMIGO DE LA EXCELENCIA. 

11112018, 01:57 PM
Post: #2




RE: Solution to the problem of preassigned variables to 0
Hello, in the first code using quotation marks the expression is not evaluated, that is to say it is kept symbolic.
PHP Code: #cas show X²/3  Y²/5 = 1 0=1 in the second code, assume X as symbolic, there is no need to use ' ' this same procedure should work assuming X as noValue PHP Code: #cas show X²/3  Y²/5 = 1 LO SUFICIENTEMENTE BUENO ES ENEMIGO DE LA EXCELENCIA. 

11112018, 06:20 PM
Post: #3




RE: Solution to the problem of preassigned variables to 0
Those variables behave exactly the way they do by design. Rather than trying to change the design (which I highly doubt will ever happen as the HP Prime is several years now in the market), you would be better off using nonsystem variables for what you want to do.
Graph 3D  QPI  SolveSys 

11122018, 09:07 PM
Post: #4




RE: Solution to the problem of preassigned variables to 0
Hello, Han, I do not propose to change the design, but to improve it, with the idea I propose it would be integrated NUM mode (HOME) with CAS MODE, since the idea is to use the same variables for example to expose a graphic analysis [PLOT], analysis numerical [NUM key] with symbolic analysis [CAS], simply defining the type of variable to symbolic (CAS mode) and then restart ([HOME MODE]).
sample: http://www.hpmuseum.org/forum/thread11736.html Likewise MATLAB works, this was born as a numerical software, but they incorporated the symbolic calculation engine (Maple, then MuPAD) and everything operates very well integration between NUM / CAS mode PHP Code: x=5: 0.0001: 5; LO SUFICIENTEMENTE BUENO ES ENEMIGO DE LA EXCELENCIA. 

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