# HP Forums

Full Version: HP Prime - definitely no education tool
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Two main reasons:

1.

The uppercase/lowercase mixing of variables and function names between the CAS and Home screens is incredibly confusing. I've no idea how I could explain it to beginning students in a way which made it seem natural.

2.

I can't find an easy way to graph a function and its derivative. I can create a function in the CAS screen: x*(x^2-1) -> f(x) and compute its derivative diff(f(x),x) -> g(x) and then graph them with F1(X) = f('X') and F2(x) = g('X')

Why can't I just use F2(x) = diff(F1(x),x)?

Quote:
Two main reasons:

1.

The uppercase/lowercase mixing of variables and function names between the CAS and Home screens is incredibly confusing. I've no idea how I could explain it to beginning students in a way which made it seem natural.

2.

I can't find an easy way to graph a function and its derivative. I can create a function in the CAS screen: x*(x^2-1) -> f(x) and compute its derivative diff(f(x),x) -> g(x) and then graph them with F1(X) = f('X') and F2(x) = g('X')

Why can't I just use F2(x) = diff(F1(x),x)?

1. This issue is just a matter of time. For me, it was very annoying at first. After getting used to it, it was hardly noticeable. Part of the reason for it, though, is to avoid conflicts with persistent global variables A-Z with symbolic manipulation (which generally substitutes a variable with its value if it is defined). So lower-case variables are generally undefined (unless the user defines them) which makes for much easier symbolic manipulation without having to use "restart" or "purge".

2. The lack of good documentation (although xcas has some decent documentation in French and English) made specifically for the HP Prime is where most of the blame should lie.

```f(x):=x*(x^2-1);
F1:=f;
F2:=F1';
```

That's all you need to do before you hit the [Plot] button.

Cheers,
Han

Re: 2) My calc crashes. It is warm start time. Did you actually try that?

1. Maths is complicated enough for students. The calculator should be an education tool and not a tool for freaks.

2. The imput of your example is tricky (avoiding the uppercase/lowercase-problem) but cumbersome (defining a function f, defining a function F1, defining a function F2).

3. In CAS you have to hit Shift-Alpha for upper key, which is lower key in Home-View (very very confusing).

4. Before plotting I have to activate the F2 function in Function App.

5. After pressing the plot key, my calculator crashed and reboot.

Edited: 16 Nov 2013, 10:56 p.m.

Teacher: "Freak".

Me: "Present".

Hi,
From an educational point of view, it would be great to be able to plot a function f together with it's Taylor and Pade approximates with something like this

```F1(X):=ln(1+x)
F2(x):=taylor(F1(x),x=0,5)