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Topic: Is this an exceptionally hard set of questions to answer?
Replies: 68   Last Post: Nov 11, 2002 7:54 PM

 Messages: [ Previous | Next ]
 David Redmond Posts: 23 Registered: 12/13/04
Re: Is this an exceptionally hard set of questions to answer?
Posted: Nov 2, 2002 10:01 AM

On Sat, 02 Nov 2002 09:55:50 -0500, Alberto Moreira
<junkmail@moreira.mv.com> wrote:

>Kevin Foltinek <foltinek@math.utexas.edu> said:

>>There's also the problem that students have with expanding
>>(a+b)*(c+d). Many students have memorized the pneumonic "FOIL" for
>>"First, Outer, Inner, Last", meaning to group things as (a,c), (a,d),
>>(b,c), (b,d), and then multiply and add.

snip

>>For these students, this is the kind of "magic" to which I was
>>referring, because they do not see any reason why one would do this;
>>it seems arbitrary. They see neither that this is simply three
>>applications of distribution of multiplication over addition,
>>(a+b)*(c+d) = a*(c+d)+b*(c+d) = a*c+a*d+b*c+b*d, nor that they are
>>doing (nearly) the same thing as they did when they were multiplying
>>multi-digit numbers.

snip

>....... The problem is, students confuse the
>notation and many will believe that when you write (a+b)(c+d) what
>you're asking for is a+bc+d. The issue here is not the application of
>the distributive property, the issue here is one of notation.

No, the issue here is expanding the expression by use of the
distributive property and there is no intuition involved.

Date Subject Author
9/28/02 Karl M. Bunday
9/30/02 Alberto C Moreira
9/30/02 Shmuel (Seymour J.) Metz
10/5/02 Moufang Loop
10/7/02 Shmuel (Seymour J.) Metz
9/30/02 Stephen Herschkorn
9/30/02 Magi D. Shepley
10/1/02 Karl M. Bunday
10/2/02 Kevin Foltinek
10/2/02 Karl M. Bunday
10/3/02 Alberto C Moreira
10/3/02 Kevin Foltinek
10/3/02 Jim Hunter
10/4/02 Herman Rubin
10/4/02 Alberto C Moreira
10/5/02 Herman Rubin
10/4/02 Alberto C Moreira
10/4/02 Kevin Foltinek
10/5/02 Alberto C Moreira
10/6/02 Virgil
10/6/02 Herman Rubin
10/6/02 Jim Hunter
10/6/02 Virgil
10/7/02 Kevin Foltinek
10/8/02 Alberto C Moreira
10/8/02 Kevin Foltinek
10/9/02 Alberto C Moreira
10/10/02 Kevin Foltinek
10/11/02 Alberto C Moreira
10/14/02 Kevin Foltinek
10/15/02 Alberto C Moreira
10/15/02 Kevin Foltinek
10/16/02 Alberto C Moreira
10/16/02 Kevin Foltinek
10/14/02 Kevin Foltinek
10/16/02 Alberto C Moreira
10/16/02 Kevin Foltinek
10/12/02 Shmuel (Seymour J.) Metz
10/14/02 Kevin Foltinek
10/25/02 Van Bagnol
10/25/02 Alberto C Moreira
10/26/02 Van Bagnol
10/27/02 Alberto C Moreira
10/27/02 Herman Rubin
10/28/02 Kevin Foltinek
10/29/02 Alberto C Moreira
10/24/02 Van Bagnol
10/25/02 Van Bagnol
10/26/02 Alberto C Moreira
10/28/02 Kevin Foltinek
10/29/02 Alberto C Moreira
10/29/02 Kevin Foltinek
10/31/02 Alberto C Moreira
10/31/02 Kevin Foltinek
11/2/02 Alberto C Moreira
11/2/02 David Redmond
11/3/02 Alberto C Moreira
11/3/02 Alberto C Moreira
11/4/02 Kevin Foltinek
11/2/02 Virgil
11/4/02 Kevin Foltinek
11/5/02 Alberto C Moreira
11/5/02 Kevin Foltinek
11/6/02 Alberto C Moreira
11/7/02 Kevin Foltinek
11/9/02 Alberto C Moreira
11/11/02 Kevin Foltinek
10/3/02 Kevin Foltinek
10/5/02 Magi D. Shepley