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Keith Bernstein
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 Posted April 11th, 2005 08:29 PM IP   
I hope this is the correct place to post this, nor am I sure that this is new, but I couldn't find this on the bug list.
There are 7 indeterminate forms, among which are 1^infinity, 0^0, and infinity^0. Indeterminate forms are mathematical expressions that are not defined. On the TI-89, each of these three forms are evaluated as 1, which is clearly incorrect. The other four: 0/0, infinity/infinity, 0*infinity, and (infinity minus infinity) all correctly evaluate to "undef".
This appears to be something that TI could easily fix if they so desired.
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paultwang
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Registered: Feb 2005 |
Posted April 12th, 2005 07:47 AM IP
They all carry the warning, which you should read.
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Keith Bernstein
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Posted April 12th, 2005 10:02 AM IP
What warning?
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paultwang
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Posts: 8
Registered: Feb 2005 |
Posted April 13th, 2005 07:21 AM IP
Warning: 0^0 replaced by 1
Warning: 1^Inf or 1^undef replaced by 1
Warning: Inf^0 or undef^0 replaced by 1
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Keith Bernstein
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Posted April 13th, 2005 01:41 PM IP
You're correct. I missed the tiny warnings underneath. I didn't think that I was the first to notice this problem.
It so happens that there is reference to 1^infinity on the Tip List; it is item 2.24, which has a discussion of this issue by someone at TI-Cares.
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Bhuvanesh
Moderator
Posts: 117
Registered: Jul 2004 |
Posted April 22nd, 2005 10:43 AM IP
Quote:
Keith Bernstein wrote:
I hope this is the correct place to post this, nor am I sure that this is new, but I couldn't find this on the bug list.
There are 7 indeterminate forms, among which are 1^infinity, 0^0, and infinity^0. Indeterminate forms are mathematical expressions that are not defined. On the TI-89, each of these three forms are evaluated as 1, which is clearly incorrect.
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Not necessarily. The conventions for interpreting those three vary by field, but 0^0 returning 1 is in particular often quite handy. Maplesoft's Maple simplifies all three to 1, while TI's Derive 6.1 simplifies the last two to 1 and gives ? for the first one.
So, in other words, these simplifications are by design.
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TechniCalc Forum :: :: Bhuvanesh :: New(?) bug in TI-89 CAS |
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