Another Prime beginner... with a dumb question
04-28-2019, 01:04 PM
Post: #1
 rrpalma Junior Member Posts: 25 Joined: Aug 2014
Another Prime beginner... with a dumb question
Hello,

I’ve been using HP calculators since my days as an engineering student in the late 80’s. I fist started with a 15C, then a 42S, then a 28S and a 48SX. I became most familiar with the 48SX, which many years later was eventually replaced by a 50G, that is now complemented by a DM42.

I just recently purchased a physical Prime and also the Prime Pro app for iOS. The app keeps crashing when working on the CAS subsystem, but that’s a different story.

I find that I do like the Prime A LOT and that it is a very powerful device, with lots of potential and features, not only for students, but for professional engineers as well. Its interface is not as polished as the HP50G though .... YET.

I do have a couple of questions that maybe someone can help me out with (I did try to find an answer on the manual). Let’s suppose I’m working on the Function app and am graphing an equation (say a parabola):
1. Is it possible for the independent variable to be something different from “X” (upper case)?
2. If I want to find the first derivative equation, what is the best way to find it? It would seem that there’s no direct way in the fcn menu (there is such an option on the 50G), and that I need to copy/paste the original equation into CAS mode, substituting the upper case “X” for a lower case “x”?
3. If I want to graph that newly found derivative function, then I need to reverse the process mentioned in (2)?

Thank you very much.
04-29-2019, 04:51 AM
Post: #2
 cyrille de brébisson Senior Member Posts: 1,009 Joined: Dec 2013
RE: Another Prime beginner... with a dumb question
Hello,

1) In the function app, the independent variable is always uppercase X.
in CAS, you can choose your independent variable. It is x (lowercase) when not specified, but you get to choose there ( plotfunc(sin(a),a) )

2) assuming that you have entered the function in F1 in the function/symblic screen, the simplest way to get the symbolic derivative is to go in CAS and type F1' ENTER.

3) still in CAS: F2:= F1' will set F2 to the derivative of F1. press plot to see it.

Cyrille

Although I work for the HP calculator group, the views and opinions I post here are my own. I do not speak for HP.
04-29-2019, 05:49 AM
Post: #3
 rrpalma Junior Member Posts: 25 Joined: Aug 2014
RE: Another Prime beginner... with a dumb question
(04-29-2019 04:51 AM)cyrille de brébisson Wrote:  Hello,

1) In the function app, the independent variable is always uppercase X.
in CAS, you can choose your independent variable. It is x (lowercase) when not specified, but you get to choose there ( plotfunc(sin(a),a) )

2) assuming that you have entered the function in F1 in the function/symblic screen, the simplest way to get the symbolic derivative is to go in CAS and type F1' ENTER.

3) still in CAS: F2:= F1' will set F2 to the derivative of F1. press plot to see it.

Cyrille

Worked beautifully. Very elegant. Thank you so much!
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