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Topic: Linear Algebra Question
Replies: 28   Last Post: Apr 25, 2014 6:10 AM

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David C. Ullrich

Posts: 3,138
Registered: 12/13/04
Re: Linear Algebra Question
Posted: Apr 16, 2014 10:30 AM
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On Tue, 15 Apr 2014 16:40:31 -0700 (PDT), federation2005@netzero.com
wrote:

>On Sunday, April 13, 2014 11:25:51 AM UTC-5, dull...@sprynet.com wrote:
>> Just realized I've been lying to my students for years.
>> Q. Say A is a 2x2 real matrix, b is in R^2 and b <> 0.
>> Let S = {x in R^2 : Ax = b}. Is S closed under addition?
>> A: ???

>
>Perhaps you're unaware of how ordinary you (and this) are. Even texts and monographs are filled with errors of this sort and worse (even dictionaries!)


Or who knows, maybe I _am_ aware of that. Maybe I pointed out
that I'd got this wrong in class many times for a reason.

Who knows?

>The worst of the lot, when it comes to math and science publishing, is Cambridge University Press (out of England) whose monographs are frequently filled with whoppers of errors (e.g. a definitive reference on exact solutions in general relativity, considered the bible of the subject by many, giving the wrong formula for the Riemann curvature tensor(!) and a completely wrong account of what a Lie derivative is(!!); other examples cover fields in math, comp. sci. as well).



Date Subject Author
4/13/14
Read Linear Algebra Question
David C. Ullrich
4/13/14
Read Re: Linear Algebra Question
Math Lover
4/13/14
Read Re: Linear Algebra Question
Bart Goddard
4/13/14
Read Re: Linear Algebra Question
magidin@math.berkeley.edu
4/13/14
Read Re: Linear Algebra Question
George Cornelius
4/14/14
Read Re: Linear Algebra Question
David C. Ullrich
4/14/14
Read Re: Linear Algebra Question
George Cornelius
4/15/14
Read Re: Linear Algebra Question
David C. Ullrich
4/15/14
Read Re: Linear Algebra Question
Paul
4/15/14
Read Re: Linear Algebra Question
quasi
4/15/14
Read Re: Linear Algebra Question
David C. Ullrich
4/15/14
Read Re: Linear Algebra Question
quasi
4/15/14
Read Re: Linear Algebra Question
Bart Goddard
4/15/14
Read Re: Linear Algebra Question
Peter Percival
4/15/14
Read Re: Linear Algebra Question
Paul
4/15/14
Read Re: Linear Algebra Question
Bart Goddard
4/20/14
Read Re: Linear Algebra Question
Shmuel (Seymour J.) Metz
4/21/14
Read Re: Linear Algebra Question
Bart Goddard
4/21/14
Read Re: Linear Algebra Question
Shmuel (Seymour J.) Metz
4/23/14
Read Re: Linear Algebra Question
Bart Goddard
4/24/14
Read Re: Linear Algebra Question
Shmuel (Seymour J.) Metz
4/24/14
Read Re: Linear Algebra Question
Bart Goddard
4/25/14
Read Re: Linear Algebra Question
Shmuel (Seymour J.) Metz
4/15/14
Read Re: Linear Algebra Question
Roland Franzius
4/15/14
Read Re: Linear Algebra Question
Peter Percival
4/15/14
Read Re: Linear Algebra Question
David C. Ullrich
4/15/14
Read Re: Linear Algebra Question
Rock Brentwood
4/15/14
Read Re: Linear Algebra Question
Rock Brentwood
4/16/14
Read Re: Linear Algebra Question
David C. Ullrich

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