Orientation III Quiz

course Phy 201

I thought my next question button wasn't going to the next question so I ended up skipping questions 2 and 3. Is there any way to go back?

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Your work has been received. Please scroll through the document to see any inserted notes (inserted at the appropriate place in the document, in boldface) and a note at the end. The note at the end of the file will confirm that the file has been reviewed; be sure to read that note. If there is no note at the end, notify the instructor through the Submit Work form, and include the date of the posting to your access page.

assignment #001

001. Only assignment: prelim asst

qa prelim

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21:10:43

`q001. Part 1 includes six activities. If you have completed an activity, just enter the answer 'completed'.

This question is appearing in the Question box. The box to the right is the Answer box, where you will type in your answers to the questions posed here.

To use this program you read a question, then enter your answer in the Answer box and click on Enter Answer. In your answers give what is requested, but don't go into excruciating detail. Try to give just enough that the instructor can tell that you understand an item.

After entering an answer click on Next Question/Answer above the Question box.

Do you understand these instructions?

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RESPONSE -->

Yes.

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21:13:28

This program has created the folder c:\vhmthphy on your hard drive.

Browse to that folder and locate the file whose name begins with SEND. The name of this file will also include your name, as you gave it to the program, and the file will show as a Text file.

Never tamper with a SEND file in any way. It contains internal codes as if these codes are tampered with you won't get credit for the assignment. However you are welcome to copy this file to another location and view it, make changes, etc. Just be sure that when requested to do so you send the instructor the original, tamper-free file.

State in the Answer box whether or not you have been able to locate the SEND file. Don't send the SEND file yet. Note that more questions/instructions remain in the q_a_prelim.

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RESPONSE -->

File found.

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21:17:03

`q002. Note that every time you click on Enter Answer the program writes your response to your SEND file. Even if the program disappears all the information you have entered with the Enter Answer button will remain in that file. This program never 'unwrites' anything. Even if this program crashes your information will still be there in the SEND file. Explain this in your own words.

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RESPONSE -->

My info that has been typed will be written to my SEND file. If the program is deleted my info I entered will remain in the SEND file. The program does not overwrite or delete anything. If the program fails my info will still be located in the SEND file.

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21:20:08

Any time the instructor does not post a response to your access site by the end of the following day, you should resubmit your work using the Submit Work form, and be sure at the beginning to indicate that you are resubmitting, and also indicate the date on which you originally submitted your work.

If you don't know where your access site is or how to access it, go to

http://www.vhcc.edu/dsmith/_vti_bin/shtml.dll/request_access_code.htm and request one now. You can submit the q_a_prelim without your access code, but other assignments should contain your code.

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RESPONSE -->

OK.

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21:22:44

`q003. If you are working on a VHCC computer, it is probably set up in such a way as to return to its original configuration when it is rebooted. To avoid losing information it is suggested that you back up your work frequently, either by emailing yourself a copy or by using a key drive or other device. This is a good idea on any computer. Please indicate your understanding of this suggestion.

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RESPONSE -->

If using a computer at VHCC, it usually reboots to original config. Use jump drive, email myself a copy or use another type of device. This is good to do on any computer. Yes, I understand.

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assignment #001

001. typewriter notation

qa initial problems

01-13-2007

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assignment #002

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01-13-2007

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assignment #001

001. Rates

qa rates

01-13-2007

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assignment #001

001. Rates

qa rates

01-13-2007

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assignment #001

001. typewriter notation

qa initial problems

01-13-2007

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23:25:56

`q001. Explain the difference between x - 2 / x + 4 and (x - 2) / (x + 4). The evaluate each expression for x = 2.

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RESPONSE -->

The first expression can be interpreted as x - (2 / x) + 4 because there are no parenthesis to separate the expression. If x = 2 then this expression would = 5. The next expression consists of parenthesis. The equations in parethesis must be done first before they can be divided. If x = 2 then the equation would be (2-2) / (2 + 4) = 0 / 6 = 0

confidence assessment: 3

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23:31:54

The numerator is 3. x isn't part of the fraction. / indicates division, which must always precede subtraction. Only the 3 is divided by [ (2x-5)^2 * 3x + 1 ] and only [ (2x-5)^2 * 3x + 1 ] divides 3.

If we mean (x - 3) / [ (2x-5)^2 * 3x + 1 ] - 2 + 7x we have to write it that way.

The preceding comments show that the denominator is [ (2x-5)^2 * 3x + 1 ]

Evaluating the expression for x = 2:

- 3 / [ (2 * 2 - 5)^2 * 3(2) + 1 ] - 2 + 7*2 =

2 - 3 / [ (4 - 5)^2 * 6 + 1 ] - 2 + 14 = evaluate in parenthese; do multiplications outside parentheses

2 - 3 / [ (-1)^2 * 6 + 1 ] -2 + 14 = add inside parentheses

2 - 3 / [ 1 * 6 + 1 ] - 2 + 14 = exponentiate in bracketed term;

2 - 3 / 7 - 2 + 14 = evaluate in brackets

13 4/7 or 95/7 or about 13.57 add and subtract in order.

The details of the calculation 2 - 3 / 7 - 2 + 14:

Since multiplication precedes addition or subtraction the 3/7 must be done first, making 3/7 a fraction. Changing the order of the terms we have

2 - 2 + 14 - 3 / 7 = 14 - 3/7 = 98/7 - 3/7 = 95/7.

COMMON STUDENT QUESTION: ok, I dont understand why x isnt part of the fraction? And I dont understand why only the brackets are divided by 3..why not the rest of the equation?

INSTRUCTOR RESPONSE: Different situations give us different algebraic expressions; the situation dictates the form of the expression.

If the above expression was was written otherwise it would be a completely different expression and most likely give you a different result when you substitute.

If we intended the numerator to be x - 3 then the expression would be written (x - 3) / [(2x-5)^2 * 3x + 1 ] - 2 + 7x, with the x - 3 grouped.

If we intended the numerator to be the entire expression after the / the expression would be written x - 3 / [(2x-5)^2 * 3x + 1 - 2 + 7x ].

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RESPONSE -->

Enter, as appropriate, an answer to the question, a critique of your answer in response to a given answer, your insights regarding the situation at this point, notes to yourself, or just an OK.

Always critique your solutions by describing any insights you had or errors you makde, and by explaining how you can make use of the insight or how you now know how to avoid certain errors. Also pose for the instructor any question or questions that you have related to the problem or series of problems. I didn't think my 'next question/answer' was changing so I accidentally skipped it, Sorry!

self critique assessment: 0

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23:46:08

`q004. Explain, step by step, how you evaluate the expression (x - 5) ^ 2x-1 + 3 / x-2 for x = 4.

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RESPONSE -->

Enter 4 where x appears...(4 - 5) ^ 2(4) - 1 + 3 / 4 - 2. Do parethesis first...(-1) ^ 8 - 1 + 3 / 4 - 2. Do exponents... (-1) ^ 7 + 3 / 4 - 2 which then equals -1 + (3 / 4) - 2, parethesis are used to separate to show how the expression would be interpreted. Find common denominator...(-4 / 4) + (3 / 4) - (8 / 4). Answer is - 9 / 4.

confidence assessment: 3

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23:51:00

We get

(4-5)^2 * 4 - 1 + 3 / 1 - 4

= (-1)^2 * 4 - 1 + 3 / 4 - 2 evaluating the term in parentheses

= 1 * 4 - 1 + 3 / 4 - 2 exponentiating (2 is the exponent, which is applied to -1 rather than multiplying the 2 by 4

= 4 - 1 + 3/4 - 2 noting that 3/4 is a fraction and adding and subtracting in order we get

= 1 3/4 = 7 /4 (Note that we could group the expression as 4 - 1 - 2 + 3/4 = 1 + 3/4 = 1 3/4 = 7/4).

COMMON ERROR:

(4 - 5) ^ 2*4 - 1 + 3 / 4 - 2 = -1 ^ 2*4 - 1 + 3 / 4-2 = -1 ^ 8 -1 + 3 / 4 - 2.

INSTRUCTOR COMMENTS:

There are two errors here. In the second step you can't multiply 2 * 4 because you have (-1)^2, which must be done first. Exponentiation precedes multiplication.

Also it isn't quite correct to write -1^2*4 at the beginning of the second step. If you were supposed to multiply 2 * 4 the expression would be (-1)^(2 * 4).

Note also that the -1 needs to be grouped because the entire expression (-1) is taken to the power. -1^8 would be -1 because you would raise 1 to the power 8 before applying the - sign, which is effectively a multiplication by -1.

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RESPONSE -->

I thought the 2x - 1 was all the exponent due to the large space that was between the 1 and the plus sign. I understand what I did.

self critique assessment: 2

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23:52:52

*&*& Standard mathematics notation is easier to see. On the other hand it's very important to understand order of operations, and students do get used to this way of doing it.

You should of course write everything out in standard notation when you work it on paper.

It is likely that you will at some point use a computer algebra system, and when you do you will have to enter expressions through a typewriter, so it is well worth the trouble to get used to this notation.

Indicate your understanding of the necessity to understand this notation.

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RESPONSE -->

Yes, I understand.

self critique assessment: 3

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Good work on the problems that were included. You gave reasonable answers and your self-critiques were good.

Let me know if you have questions.