Re: A C H A L L E N G E

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Re: A C H A L L E N G E

Ivan Cibrario Bertolotti wrote:
>
> Hello,
>
> Rene Kragh Pedersen wrote:
> >
> > Eric Chu wrote:
> > >
> > > Hello, TI people.
> > >
>   [...]
>
> > > Eric Chu
> >
> > Now come on please, get real. You start of by letting us all know you
> > think the HP is superior. It's evident that you aren't going to listen
> > to us no matter what.
> > However, I want to try and make a few points anyway (how dumb it might
> > ever seem :)
> >
> > You start out by comparing your TI-85 to your HP-48GX and naturally your
> > choice has to be the HP. Naturally. But that's like comparing a 486 to a
> > P5...Try comparing realistically, for example with TI-92.
> > That's when we can start talking, when you compare two equivalent
> > calculators, both in functions and time of release into the market.
>
> I don't know when the TI-85 was released exactly, but I want to
> point out that the HP48S/SX were released more than four years ago,
> when the TI-92 didn't exist yet.

But this was about the GX...The TI-85 is old too, don't know how old
though.

> Moreover, while the TI-92 is more
> oriented towards symbolic manipulations, the HP48 is more oriented
> towards numeric calculations, therefore in my opinion the calculators
> you want to compare are NOT so equivalent, neither in functions nor
> in time of release.

What I mean is, they do the same, I never said anything about
orientation.
Equivalency, however, is always a matter of opinion, let's leave it.

> > Example:
> > Today I had a math assignment to deliver (I study at the university),
> > part of it involved an equation where the solutions were possible limits
> > for the expression we were examining. We knew from an earlier part.that
> > 3 would be a good guess.
> >
> > The equation reduced to:
> > (a-1)^3 = a+5
> >
> > I'm lazy, so I don't want to hand-calc (a-1)^3, I just type it on my
> > TI-92, pressing: F2 3 (a-3)^3) <ENTER>
> > on the screen it said:
> > expand((a-1)^3)
> > and the result was:
> > a^3 - 3a^2 + 3a - 1
> > Now, to reduce the right side of my equation to zero, I wanted to move
> > (a+5) over, so I pressed <up> <ENTER> - (a+5) <ENTER>
> > result:
> > a^3 - 3a^2 +2a - 6
> > Now, the in the assignment we had to utilize the hunch that 3 was a
> > solution, so we needed to divide the expression with (a-3)
> > Well, F2 2 <up> <ENTER> , a-3) <ENTER>
> > and voila:
> > (a-3)(a^2+2)=0
> >
> > EXACTLY the expression I needed with minimum keypresses.
> >
> > Try doing it on your HP and see how easy it is to follow and write
> > down...One of the other guys here has one and he just said: "well, maybe
> > I could write a program that does it *smiling* but no..."
> >
>
> I absolutely don't want to start a new flame war between HP and TI
> lovers; I owned both of them and enjoyed using both. However, solving
> your problem with an HP48 is not so difficult:
>
> - first of all enter the coefficients of ((a-1)^3) as a vector:
>    [1 -3 3 -1] (about 12 keystrokes)
>
> - then enter the coefficients of a+5, again as a vector:
>    [0 0 1 5] (about 10 keystrokes)
>
> - hit '-' to subtract the two polynomials (1 keystroke); you obtain:
>    [1 -2 2 -6] on the stack
>
> - execute the function PROOT (three keystrokes); you obtain:
>    [(0, 1.41...) (0, -1.41...) (3,0)]
>   This is a vector that represents the three solutions of your
>   polynomial: i Sqrt[2], -i Sqrt[2] and 3; two of them are complex
>   roots, while the last is a real number. This obviously corresponds
>   to the symbolic expression (a^2 + 2)(a - 3) = 0 with the first
>   factor factored in the complex domain, too.
>
> Neither the 'hint' you used nor the 'program' you mentioned are
> needed in any way.

I was unclear here, seems I left out the REAL point: The difference is
that it is much easier to see what is going on on the TI-92.
It takes about thirty strokes on both calcs, but on the TI it's easy too
see that you're actually processing the numbers the way you think you
are, and the output is directly transferrable to your paper.
Also, this can be utilized in the Text Editor, where command lines can
be inserted too. Essentially, they do the same. The TI is more
userfriendly but probably a bit slower. I don't mind, some do, and
that's it...
Finally, I'm certain you learn more by using your calc, if the steps are
actually visible on-screen.

> I just want to say that, in order to compare two different tools in
> any way, as a minimum you must be able to use well BOTH of them.

Or you could ask someone how he does, like I did ...

> I agree with you that the TI-92 is easier to use; however, I think
> this isn't the right example to support this opinion.

BTW: I'm also curious as to whether you just punched on and got your
result right away the first time, or...

I did, and I'm sure anyone could have done too.

Unless you have some comments on this, don't answer the post, we're
_ALMOST_ starting the good old discussion again, somebody's bound to get
hooked...

--
          Rene Kragh Pedersen
------------------------------------------------
.oO) Who is General Failure, and why is he reading my disk? (Oo.
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