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From: Bastian Erdnuess on 30 Nov 2009 14:15
Hi,

On the HP 28S is a command called FORM. Does anybody here knows it? It
is used to reformat expressions. E.g. with it you can pretty easy
transform 'X+Y' into 'Y+X'. I now have had a hard time trying to
transform '1/(SQRT(2*pi)*EXP(X^2/2))' into '1/SQRT(2*pi)*EXP(-X^2/2)' on
the HP 50g, but no chance. Does anybody know how to do this?

I found the equation writer (EQW) and the algebra menu (ALG) containing
beside others COLLECT and EXPAND. I also went over the fifth chapter of
HP 50g's user guide ("Algebraic and arithmetic operations") but I didn't
find anything useful in there.

Thanks for any hint,
Bastian

PS: There is no point doing THIS transformation. I just want to know,
how to do transformations like that in general.
From: ddoherty03 on 2 Dec 2009 20:52
On Nov 30, 1:15 pm, earth...(a)web.de (Bastian Erdnuess) wrote:
> Hi,
>
> On the HP 28S is a command called FORM.  Does anybody here knows it?  It
> is used to reformat expressions.  E.g. with it you can pretty easy
> transform 'X+Y' into 'Y+X'.  I now have had a hard time trying to
> transform '1/(SQRT(2*pi)*EXP(X^2/2))' into '1/SQRT(2*pi)*EXP(-X^2/2)' on
> the HP 50g, but no chance.  Does anybody know how to do this?
>
> I found the equation writer (EQW) and the algebra menu (ALG) containing
> beside others COLLECT and EXPAND.  I also went over the fifth chapter of
> HP 50g's user guide ("Algebraic and arithmetic operations") but I didn't
> find anything useful in there.
>

I'm not sure what you mean by you "found the equation writer". You
can use
it pretty easily to do this sort of thing by selecting the (X^2/2)
subexpresion
with the arrow keys, then hitting the '+-' key.

If you mean doing programaticly, I don't know.

Regards,

Dan
From: Bastian Erdnuess on 3 Dec 2009 02:03
Thank you, for your respond.

ddoherty03 <ddoherty03(a)gmail.com> wrote:

> On Nov 30, 1:15 pm, earth...(a)web.de (Bastian Erdnuess) wrote:
> > Hi,
> >
> > On the HP 28S is a command called FORM. Does anybody here knows it? It
> > is used to reformat expressions. E.g. with it you can pretty easy
> > transform 'X+Y' into 'Y+X'. I now have had a hard time trying to
> > transform '1/(SQRT(2*pi)*EXP(X^2/2))' into '1/SQRT(2*pi)*EXP(-X^2/2)' on
> > the HP 50g, but no chance. Does anybody know how to do this?
> >
> > I found the equation writer (EQW) and the algebra menu (ALG) containing
> > beside others COLLECT and EXPAND. I also went over the fifth chapter of
> > HP 50g's user guide ("Algebraic and arithmetic operations") but I didn't
> > find anything useful in there.
> >
>
> I'm not sure what you mean by you "found the equation writer".

I'm not sure, either. I think it shell mean something like "I'm aware
that it exists, but I don't see how to use it to do what I want".

> You can use
> it pretty easily to do this sort of thing by selecting the (X^2/2)
> subexpresion with the arrow keys, then hitting the '+-' key.

But this changes the expression.

How it is, is that in '1/(SQRT(2*pi)*EXP(X^2/2))' the EXP is in the
denominator. But what I want is, to have the EXP in the nominator, just
with opposite sign. When I do what you explain then the EXP is still in
the denominator, but with opposite sign. That's not what I want.

> If you mean doing programaticly, I don't know.

No, just by hand.

Regards,
Bastian
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