021 query 21

#$&*

course Mth 151

4/19 10

If your solution to stated problem does not match the given solution, you should self-critique per instructions at

http://vhcc2.vhcc.edu/dsmith/geninfo/labrynth_created_fall_05/levl1_22/levl2_81/file

3_259.htm

Your solution, attempt at solution. If you are unable to attempt a solution, give a

phrase-by-phrase interpretation of the problem along with a statement of what you do

or do not understand about it. This response should be given, based on the work you

did in completing the assignment, before you look at the given solution.

021. `query 21

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Question: `q4.4.6 star operation [ [1, 3, 5, 7], [3, 1, 7, 5], [5, 7, 1, 3], [7, 5,

3, 1]]

YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

Your solution:

identity is 1 and all numbers can be inversed

confidence rating #$&*: 3

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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Given Solution:

`a** Using * to represent the operation the table is

* 1 3 5 7

1 1 3 5 7

3 3 1 7 5

5 5 7 1 3

7 7 5 3 1

the operation is closed, since all the results of the operation are from the

original set {1,3,5,7}

the operation has an identity, which is 1, because when combined with any number 1

doesn't change that number. We can see this in the table because the row

corresponding to 1 just repeats the numbers 1,3,5,7, as does the column beneath 1.

The operation is commutative--order doesn't matter because the table is symmetric

about the main diagonal..

the operation has the inverse property because every number can be combined with

another number to get the identity 1:

1 * 1 = 1 so 1 is its own inverse;

3 * 3 = 1 so 3 is its own inverse;

5 * 5 = 1 so 5 is its own inverse;

7 * 7 = 1 so 7 is its own inverse.

This property can be seen from the table because the identity 1 appears exactly once

in every row.

the operation appears associative, which means that any a, b, c we have (a * b ) * c

= a * ( b * c). We would have to check this for every possible combination of a, b,

c but, for example, we have (1 *3) *5=3*5=7 and 1*(3*5)=1*7=7, so at least for a =

1, b = 3 and c = 5 the associative property seems to hold. **

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Self-critique (if necessary):OK

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Self-critique Rating:3

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Question: `q4.4.24 a, b, c values that show that a + (b * c) not equal to (a+b) *

(a+c).

YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

Your solution:

0+(1+2)=3

(0+1)*(0+2)=2

confidence rating #$&*:

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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Given Solution:

`a** For example if a = 2, b = 5 and c = 7 we have

a + (b + c) = 2 + (5 + 7) = 2 + 12 = 14 but

(a+b) * (a+c) = (2+5) + (2+7) = 7 + 12 = 19. **

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Self-critique (if necessary):OK

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Self-critique Rating:3

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Question: `q4.4.33 venn diagrams to show that union distributes over intersection

YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

Your solution:

all of A and AB and AC

confidence rating #$&*: 3

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Given Solution:

`a** For A U (B ^ C) we would shade all of A in addition to the part of B that

overlaps C, while for (A U B) ^ (A U C) we would first shade all of A and B, then

all of A and C, and our set would be described by the overlap between these two

shadings. We would thus have all of A, plus the overlap between B and C. Thus the

result would be the same as for A U (B ^ C). **

"

Self-critique (if necessary):

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Self-critique rating:

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Question: `q4.4.33 venn diagrams to show that union distributes over intersection

YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

Your solution:

all of A and AB and AC

confidence rating #$&*: 3

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.............................................

Given Solution:

`a** For A U (B ^ C) we would shade all of A in addition to the part of B that

overlaps C, while for (A U B) ^ (A U C) we would first shade all of A and B, then

all of A and C, and our set would be described by the overlap between these two

shadings. We would thus have all of A, plus the overlap between B and C. Thus the

result would be the same as for A U (B ^ C). **

"

Self-critique (if necessary):

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Self-critique rating:

#*&!

&#Good responses. Let me know if you have questions. &#