Re: TI-M: TI-89 root question
[Prev][Next][Index][Thread]
Re: TI-M: TI-89 root question
Yes you are correct. The TI-92, 92+ and 89 does evaluate right to left.
3
2
So 4^2^3 is 4 and gives the answer 65536
I should have double checked.
Thanks.
----- Original Message -----
From: "Scott Noveck" <noveck@pluto.njcc.com>
To: <ti-math@lists.ticalc.org>
Sent: Thursday, June 08, 2000 6:51 PM
Subject: Re: TI-M: TI-89 root question
>
> > On the TI calculators while x^n has highest prescedence. x^a^b^c^d...
etc
> > sequece is evaluated left to right. The HP48X does the same for
algebraic
> > evaluation.
>
> That is NOT true, and I'd advise you to check before generalizing like
that.
> On _SOME_ TI calculators - NOT ALL! - and the HP48X line it is evaluated
> left to right. This gives the WRONG answer, on the z80 calcs, but it's
> taken as right associative on the 68k calcs and evaluated properly.
>
> > At the TI web site it is recommend that such should be put in
parenthesis.
> > So 4^2^3 should be witten as (4^2)^3 or 4^(2^3) if that is how you want
it
> > evaluated.
>
> That's just TI covering up for their mistake =)
>
> > Also the TI-82, TI-85 will evaluate a 10/2A, A being equal to 3, as
> > 1.666.... Where as the TI-83, TI-83+, TI-86, TI-92, TI-92+, TI_89 as
15.
> > The TI-82, TI-85 parsed as one might write an implied multipication in a
> > division. The other TI's interpret 10/2A the same as 10/2*A.
>
> FYI - and I know a lot of people here will argue this point with me and
have
> a hard time accepting it (as did I) - the relative precedence of
> multiplication and division is not defined. IE, neither of those
answers -
> 1.666... and 15 - is any more "correct" than the other.
>
> Most all schools teach PEMDAS for the basic precedence laws; however, some
> teach that multiplication comes _before_ parentheses, and some teach that
> they're both done _at the same time_. I myself have always been taught
the
> latter - that they have equal precedence and are evaluated left to right,
as
> newer calcs default to. Yet I have heard of many textbooks that teach
that
> multiplication always comes before division.
>
> There was a large debate over this on news://sci.math a few months back.
> Apparently, from what I gathered from some college professors, the
majority
> concensus used to be that multiplication had a higher precedence, unlike
how
> the new CAS's evaluate it. The major turning point was the onset of the
> computer language Fortran, which gave both equal precedence. Most later
> languages, including BASIC and C/C++, have followed in suit and it is
> generally believed that the majority today gives equal precendence, too.
>
> I'm no real authority myself, so I could be wrong, but I figure it's an
> interesting little factoid nonetheless.
>
> > TI recommens the use of the parenthesis to avoid ambiguity.
>
> This time, they're correct. AFAIK, when it comes to powers, they are not.
>
> -Scott
>
>
>
References: