course Phy 201 hwsFǃvЄǬassignment #001 001. Only assignment: prelim asst qa prelim
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10:51:39 `questionNumber 10001 `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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10:54:00 `questionNumber 10001 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 --> yes
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10:55:28 `questionNumber 10002 `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 --> The send file contains all information that is entered in the answer box on the right side of the screen. If the program closes the file automatically saves itself to the send file.
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Ęvz_ĸM assignment #001 001. typewriter notation qa initial problems 08-22-2008
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13:20:47 `questionNumber 10000 `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 --> When I see the word difference I think about a subtraction problem but I have been out of school for a while so i don't know if thats what you are asking. There are two different ways that I see to answer the question. First there is the difference between the two sides of the equation and how you would go about answering the question. The first thing I feel we should do is substitute the value two for X. So with our first equation reading 2-2 / 2+4 we should proceed to follow the order of operations and do the division first so that would leave 2-1+4 and then proceed with the order of operations and work from left to right leaving us with 2-1=1+4 and the answer 5. With the second equation the order of operations tells us that we must work the question of the bracets with X=2 it would be (2-2) / (2+4) so 0 / 6 leaving us with 0. So that is the difference in the way you would work the problems. If the question is in fact a question of subtraction it would be 5-0 leaving a difference of 5. confidence assessment: 2
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13:22:50 `questionNumber 10000 The order of operations dictates that grouped expressions must be evaluated first, that exponentiation must be done before multiplication or division, which must be done before addition or subtraction. It makes a big difference whether you subtract the 2 from the x or divide the -2 by 4 first. If there are no parentheses you have to divide before you subtract. Substituting 2 for x we get 2 - 2 / 2 + 4 = 2 - 1 + 4 (do multiplications and divisions before additions and subtractions) = 5 (add and subtract in indicated order) If there are parentheses you evaluate the grouped expressions first: (x - 2) / (x - 4) = (2 - 2) / ( 4 - 2) = 0 / 2 = 0.
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RESPONSE --> ok I understand the question now and see how the problem should be approached self critique assessment: 3
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13:33:53 `questionNumber 10000 `q002. Explain the difference between 2 ^ x + 4 and 2 ^ (x + 4). Then evaluate each expression for x = 2. Note that a ^ b means to raise a to the b power. This process is called exponentiation, and the ^ symbol is used on most calculators, and in most computer algebra systems, to represent exponentiation.
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RESPONSE --> The first thing that we must do is recognize our order of operations and work each equation seperatly. first we will replace our X with 2. So our first equation will read 2^2 + 4 and we will work our exponent first and it will be 4 + 4= 8. Our second equation will read 2^ (2 + 4) we will work our bracket first in this situation and the equation will read 2 ^ 6 which equals 64 confidence assessment: 3
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13:34:46 `questionNumber 10000 `q003. What is the numerator of the fraction in the expression x - 3 / [ (2x-5)^2 * 3x + 1 ] - 2 + 7x? What is the denominator? What do you get when you evaluate the expression for x = 2?
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RESPONSE --> I feel that I worked this equation properly. confidence assessment: 3
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܉UxSҸ assignment #001 001. typewriter notation qa initial problems 08-22-2008
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14:07:06 `questionNumber 10000 `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 --> First we must diffuse each side of the equation and then we must replace X with 2. In our first equation we will have 2 - 2 / 2+ 4. and then we must use the order of operations and complete the division first leaving is with 2 - 1 + 4 and the answer is 5. On the second equation we must again follow the order of operations and work the brackets one at a time the equation will read (2-2) / (2 + 4) and the equation will be 0 / 6 and the answer is 0. confidence assessment: 3
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14:12:12 `questionNumber 10000 `q002. Explain the difference between 2 ^ x + 4 and 2 ^ (x + 4). Then evaluate each expression for x = 2. Note that a ^ b means to raise a to the b power. This process is called exponentiation, and the ^ symbol is used on most calculators, and in most computer algebra systems, to represent exponentiation.
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RESPONSE --> First we must seperate our two equations and we must replace X with 2. The first equation will read 2 ^ 2 + 4 and with the order of operations we must work our exponents first so the equation will read 4 + 4 = 8. The second equation will be written 2 ^ (2+4). First we complete the bracket and the equation will read 2 ^ 6 witch equals 64. confidence assessment: 3
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14:26:48 `questionNumber 10000 `q003. What is the numerator of the fraction in the expression x - 3 / [ (2x-5)^2 * 3x + 1 ] - 2 + 7x? What is the denominator? What do you get when you evaluate the expression for x = 2?
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RESPONSE --> I feel the numerator is x-3 and the denominator is [ (2x-5)^2 * 3x + 1 ] - 2 + 7x and the answer to the equation would be -1/19. confidence assessment: 1
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14:28:46 `questionNumber 10000 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 --> Ok I understand this now hopefully I won't make this mistake again. self critique assessment: 3
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15:15:47 `questionNumber 10000 `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 --> First we replace the X with 4 so our equation reads (4 - 5) ^2(4) - 1 +3 / 4-2 In the order of operations the first thing we must do is the brackets that leaves (-1) ^ 2(4) - 1 +3 / 4-2 next in the order of operations would be multiplication from left to right. We would see -1^ 8 -1 +3 / 4-2. So first we would multiply -1 times 8 and then we will divide 3/4 and our equation will read -8 -1 + .75 -2. Then we will move from left to right with addition and subtraction. So we will see - 8.25 -2 = -10.25 for our final answer. confidence assessment: 2
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15:22:21 `questionNumber 10000 *&*& 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 --> Ok I see the problem with the first step of the problem but i don't understand why we do not work it all the way down to the number 1.75 self critique assessment: 0
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15:24:48 `questionNumber 10000 `q005. At the link http://www.vhcc.edu/dsmith/genInfo/introductory problems/typewriter_notation_examples_with_links.htm (copy this path into the Address box of your Internet browser; alternatively use the path http://vhmthphy.vhcc.edu/ > General Information > Startup and Orientation (either scroll to bottom of page or click on Links to Supplemental Sites) > typewriter notation examples and you will find a page containing a number of additional exercises and/or examples of typewriter notation.Locate this site, click on a few of the links, and describe what you see there.
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RESPONSE --> There is a series of type writer and standard notations showing the simplfying of the numerical values. confidence assessment: 3
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15:25:44 `questionNumber 10000 end program
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RESPONSE --> I have seen the series of pictures self critique assessment: 3
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