[Request] for renaming variables

[Joe Horn]

(05-29-2014 03:46 PM)Angus Wrote:  I refer to Joe Horn's post

Quote:All are legal, and all retain their values (and names!) in both modes, with the first three remaining Home vars, and the other three remaining CAS vars, as can be seen by pressing the Vars key, or via the Memory Manager.

Doesn't that mean, that if I define a variable X in the cas it does NOT coexist with a home variable X??? So a single letter variable in capital letter refers to the home variable, althogh it it used/created in the cas?
Man I thought I got it....

You can't define a variable X in CAS. Creating two variables with the same name, one in Home, and one in CAS, is impossible to do. If you're in CAS, and you store a number into X, then it gets stored into the Home variable X.

Related factoid: Since Home numeric (real, floating-point) variables are 12-digit BCD, and CAS numeric variables are 48-bit binary, this can cause surprising changes to values. Example:

In CAS:
X:=1/3. (include the decimal point to force numeric approximation)
X-1/3. --> not zero, because 1/3. in Home <> 1/3. in CAS.

I hope that didn't make it even more confusing.