Why did they separate Cas and non-cas?

[DeucesAx]

I googled and searched this forum without finding a satisfying answer. What are the advantages of separating the two modes?

[Joe Horn]

A discussion on that topic was held last December before the board went to the new software: http://www.hpmuseum.org/cgi-sys/cgiwrap/...591#257591

[DeucesAx]

Is that it? It boils down to me either wanting 3.46... or 2*sqrt(3)? Why not just something more like press enter for exact and shift enter for approx? (I don't even have the calculator yet it arrives Monday, but I really need to hit the ground running with it)
Can I turn off the default setting that each variable is initialized as 0 in the home mode? Im scared I forget about that in an exam.

[Joe Horn]

(02-16-2014 03:25 AM)DeucesAx Wrote:  Is that it? It boils down to me either wanting 3.46... or 2*sqrt(3)? Why not just something more like press enter for exact and shift enter for approx?

Good news: They must have either read your mind, or you read theirs. You can do exactly what you suggested in CAS. Check it out:

\(\sqrt{12}\) Enter --> \(2\sqrt{3}\)
\(\sqrt{12}\) Shift Enter --> 3.46410161514
\(\sqrt{12}\) Enter [a b/c] --> both answers (best of both worlds!)

HP made it exactly the way you suggested. Cool, huh?

Quote:Can I turn off the default setting that each variable is initialized as 0 in the home mode?

No, because the built-in Home variables are like the 4 stack levels in traditional RPN calculators, always existing and always containing something. Prime's A through Z always exist, and contain zero until you replace the zero with some other real number; Z0 through Z9 always exist and contain zero until you store a complex number in them; and so on.

Quote:Im scared I forget about that in an exam.

No problem: to avoid accidentally using a variable that you didn't initialize, stick to user-created variables, which can nicely have descriptive names, and do not exist until you store something in them, and cease to exist when they are deleted.

[Dominik Holenstein]

Here is a similar apporach if Exact is checked in your CAS settings:

\(\sqrt{12}\) Enter --> \(2\sqrt{3}\) --> symbolic result
[a b/c] --> 3.46410161514 --> numeric result
[a b/c] --> 3650401 / 1053780 --> exact result

See the attached screenshot.

Best,
Dominik

[DeucesAx]

Thank you. I guess for now Ill just use the CAS mode at all times.
Could you give some examples where it would be advantageous to use both at the same time?

[eried]

:O maybe this separation (illogical from an engineer viewpoint) was to offer the ability to block the CAS :O? (I realized this thinking on how TI handled this... 2 different calculators, one without CAS, one with... a much worse decision, imagine if you got the non-cas as a gift, instant boomer; but at last something kinda required by education viewpoint)

[John R. Graham]

One other nuance is that CAS mode doesn't currently support RPN entry: if you want exact results, you're stuck with algebraic entry—and extra keystrokes.

- John