Assignment 2 R1

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course Mth 158

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/file3_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.

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Question: * R.1.26 \ was R.1.14 (was R.1.6) Of the numbers in the set {-sqrt(2), pi + sqrt(2), 1 / 2 + 10.3} which are counting numbers, which are rational numbers, which are irrational numbers and which are real numbers?

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Your solution:

(a) Natural Numbers = None

(b) Integers = None

(c) Rational Numbers = ½ + 10.3

(d) Irrational Numbers = -sqrt(2), pi + sqrt(2)

(e) Real Numbers = -sqrt(2), pi + sqrt(2), ½ + 10.3

confidence rating #$&*:: 3

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Given Solution:

* * ** Counting numbers are the numbers 1, 2, 3, .... . None of the given numbers are counting numbers

Rational numbers are numbers which can be expressed as the ratio of two integers. 1/2+10.3 are rational numbers.

Irrational numbers are numbers which can be expressed as the ratio of two integers. {-sqrt(2)}, pi+sqrt(2) are irrational numbers.. **

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Self-critique (if necessary): OK

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Self-critique Rating: OK

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Question: * R.1.44 \ 32 (was R.1.24) Write in symbols: The product of 2 and x is the product of 4 and 6

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Your solution:

2*x = 4*6

confidence rating #$&*:: 3

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Given Solution:

* * ** The product of 2 and x is 2 * x and the product of 4 and 6 is 4 * 6. To say that these are identical is to say that 2*x=4*6. **

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Self-critique (if necessary): OK

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Self-critique Rating: OK

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Question:

* R.1.62 \ 50 (was R.1.42) Explain how you evaluate the expression 2 - 5 * 4 - [ 6 * ( 3 - 4) ]

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Your solution:

2 - 5 * 4 - [6 * (3 - 4)]

2 - 20 - [6 * -1]

2 - 20 - (-6)

-18 + 6

= -12

confidence rating #$&*: 3

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Given Solution:

* * **Starting with

2-5*4-[6*(3-4)]. First you evaluate the innermost group to get

2-5*4-[6*-1] . Then multiply inside brackets to get

2-5*4+6. Then do the multiplication to get

2-20+6. Then add and subtract in order, obtaining

-12. **

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Question:

* R.1.98 \ 80 (was R.1.72) Explain how you use the distributive property to remove the parentheses from the express (x-2)(x-4).

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Your solution:

(x - 2) (x - 4)

x ^ 2 - 4x - 2x + 8

= x ^ 2 - 8x + 8

confidence rating #$&*: 3

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Given Solution:

* * ** COMMON ERROR: Using FOIL. FOIL is not the Distributive Law. FOIL works for binomial expressions. FOIL follows from the distributive law but is of extremely limited usefulness and the instructor does not recommend relying on FOIL.

Starting with

(x-2)(x-4) ; one application of the Distributive Property gives you

x(x-4) - 2(x-4) . Applying the property to both of the other terms we get

x^2 - 4x - (2x -8). Simplifying:

x^2 - 4x - 2x + 8 or

x^2 - 6x + 8. *

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Self-critique (if necessary):

I used foil to solve this equation. As the common error states I’m suppose to use the Distributive Law, which I’m not sure I’ll remember. Just because I’ve used Foil for so long. The following is how to solve with the Distributive Law:

(x - 2) ( x - 4)

x(x - 4) - 2(x - 4)

x ^ 2 - 4x - (2x - 8)

x ^ 2 - 6x - 8.

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Self-critique Rating: 3

@& Foil won't work with expressions like (x + 3) * ( x^2 + 3 x - 5). Gotta use the distributive law.*@

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Question:

* R.1.102 \ 86 (was R.1.78) Explain why (4+3) / (2+5) is not equal to 4/2 + 3/5.

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Your solution:

With (4 + 3) / (2 + 5) all you have to do is add the numbers to get 7/7 = 1.

However to get 4/2 + 3/5 you must find a common denominator. The common denominator in this case is 10. So you must do the following:

4/2 * 5/5 = 20/10 & 3/5 * 5/5 = 6/10

20/10 + 6/10 = 26/10

26/10 = 2 3/5

confidence rating #$&*: 3

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Given Solution:

* * ** Good answer but at an even more fundamental level it comes down to order of operations:

(4+3)/(2+5) means

7/7 which is equal to

1.

By order of operations, in which multiplications and divisions precede additions and subtractions,

4/2+3/5 means

(4/2) + (3/5), which gives us

2+3/5 = 2 3/5

* Add comments on any surprises or insights you experienced as a result of this assignment.

"

Self-critique (if necessary):

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Self-critique rating:

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Question:

* R.1.102 \ 86 (was R.1.78) Explain why (4+3) / (2+5) is not equal to 4/2 + 3/5.

YYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY

Your solution:

With (4 + 3) / (2 + 5) all you have to do is add the numbers to get 7/7 = 1.

However to get 4/2 + 3/5 you must find a common denominator. The common denominator in this case is 10. So you must do the following:

4/2 * 5/5 = 20/10 & 3/5 * 5/5 = 6/10

20/10 + 6/10 = 26/10

26/10 = 2 3/5

confidence rating #$&*: 3

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

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Given Solution:

* * ** Good answer but at an even more fundamental level it comes down to order of operations:

(4+3)/(2+5) means

7/7 which is equal to

1.

By order of operations, in which multiplications and divisions precede additions and subtractions,

4/2+3/5 means

(4/2) + (3/5), which gives us

2+3/5 = 2 3/5

* Add comments on any surprises or insights you experienced as a result of this assignment.

"

Self-critique (if necessary):

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Self-critique rating:

#*&!

&#Your work looks good. See my notes. Let me know if you have any questions. &#