On Sun, 03 Dec 2006 05:27:54 -0800, David Joyner <[EMAIL PROTECTED]>
wrote:
> Bobby Moretti wrote:
>>>> These are all good reasons... I wish there was a better way than
>>>> having a predefined list of indeterminates... I could see all sorts of
>>>> things being screwed up that way.
>>>>
>>> Such as?
>>>
>
> It's easy to imagine things that can go wrong since this is essentially
> what Maple (and Reduce/the TI92) does
> and I have lots of experience with students doing Maple worksheets in a
> computer lab.
> The problem is to make sure that they can be easily fixed. For example,
> if you want a function to be defined
> this way:
>
> f = exp(x)*sin(exp(x))
>
> a student will want f(1) to work. Will it? I'm guessing you'll have a
> function like
>
> value(f,1) or subs(1,f)
>
> or somethign like that.
Yes, f(1) will work. It actually already does in the current version
of SAGE! E.g.,
sage: f = sin(x)*cos(sin(x))
sage: f(1)
(sin(1)*cos(sin(1)))
sage: a = f(1)
sage: a
(sin(1)*cos(sin(1)))
sage: float(a)
0.56072828148897991
> This is awkward at first for them but if it is
> explained they will get used to it.
> What if they want the floating point approximation to 3 decimal places?
> Maybe
>
> value(f,1.0)
>
> or something?
No way, that's way too hard to remember. Here's what is already
implemented
in SAGE:
sage: f(1.0)
0.560728281488980
> Again, it must be explained. I can easily imagine a
> student setting x = 1 for
> some reason and then having the rest of the session messed up since x is
> no longer available to
> them to define functions with.
That's a problem in maple, mathematica, etc.
> The student will need a command to
> "clear" some of all
> predefined variables (such as clear("x") or clear_all() or something
> like that).
Clear could easily set the variable back to being an indeterminate.
> One idea, which I think students will accept, is to have a command like
>
> load_calculus()
>
> or something. This could for example
> (a) load predefined variables,
> (b) spit out a very brief screen of explanations (perhaps a list of some
> available
> commands, an explanation of how to get help in the notebook or on the
> command-line, ...),
> (c) load a bunch of teacher-defined *.sage files in examples/calculus,
> (d) other stuff?
>
> Of course, one extremely cool thing about the SAGE notebook is that you
> can actually
> design a special calculus control bar if you want. Maybe if you click on
> help, one of the items
> says calculus, and there is a link there to explain how to put a
> calculus help control bar where the
> normal control bar is .
Very interesting idea.
William
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