Assignment 6

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~T{\Q˕_assignment #006

006.

Precalculus I

02-20-2009

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17:50:33

`q001. Note that this assignment has 10 questions

Recall that the graph of y = x^2 + 3 was identical to the graph of y = x^2, except that it was raised 3 units. This function is of the form y = x^2 + c. In the case of this specific function, c = 3. What function would this form give us for c = -1? How would the graph of this function compare with the graph of y = x^2?

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RESPONSE -->

the values on a table would be less by one than those on a table of y = x^2 and on the graph everyting would shift down 1

confidence assessment: 2

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17:50:43

If c = -1 the form y = x^2 + c gives us y = x^2 - 1. Every value on a table of this function would be 1 less than the corresponding value on a table of y = x^2, and the graph of y = x^2 - 1 will lie 1 unit lower at each point then the graph of y = x^2.

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RESPONSE -->

self critique assessment: 3

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17:58:15

`q002. Suppose that we wish to graph the functions y = x^2 + c for c = -3, then for c = -2, then for c = -1, then for c = 0, then for c = 1, then for c = 2, then for c = 3. If all these functions were plotted on the same set of coordinate axes, what would the final graph look like? It is suggested that you actually sketch your graph and describe your sketch.

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RESPONSE -->

the graphs would be 1 place higher starting at c=-3 and ending at c=3

confidence assessment: 3

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17:58:46

The graph of the c= -3 function y = x^2 - 3 will lie 3 units lower than the graph of y = x^2.

The graph of the c= -2 function y = x^2 - 2 will lie 22222 units lower than the graph of y = x^2.

The progression should be obvious. The graph of the c= 3 function y = x^2 + 3 will lie 3 units higher than the graph of y = x^2.

The final graph will therefore show a series of 7 functions, with the lowest three units below the parabolic graph of y = x^2 and the highest three units above the graph of this function. Each graph will lie one unit higher than its predecessor.

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RESPONSE -->

should have described the graph in a little more detail

self critique assessment: 2

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18:02:08

`q003. The function y = (x -1)^3 is of the form y = (x -k)^3 with k = 1. What function would this form give us for k = 3? How would the graph of this function compare with that of y = x^3?

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RESPONSE -->

y = (x -3)^3 moves three places right of y = x^3

confidence assessment: 3

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18:02:19

Recall how the graph of y = (x-1)^3 lies one unit to the right of the graph of y = x^3. The k = 3 function y = (x -3)^3 will lie 3 units to the right of the graph of y = x^3.

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RESPONSE -->

self critique assessment: 3

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18:04:47

`q004. Suppose we wish to graph the functions y = (x -k)^3 for k values 2, then 3, then 4. If we graph all these functions on the same set of coordinate axes, what will the graph look like? It is suggested that you actually sketch your graph and describe your sketch.

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RESPONSE -->

the graphs all look the same, but will move 2, 3, and 4 places to towards the right

confidence assessment: 3

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18:05:43

The k = 2 graph will lie 2 units to the right of the graph of y = x^3, and the k = 4 graph will lie 4 units to the right. The three graphs will all have the same shape as the y = x^3 graph, but will lie 2, 3 and 4 units to the right.

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RESPONSE -->

I need to use the correct terminology units instead of spaces or places

self critique assessment: 2

That's a good idea, but to this point your meanings are all clear and you're doing fine.

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SyWʹsjC

assignment #006

006.

Precalculus I

02-20-2009

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21:11:35

`q001. Note that this assignment has 10 questions

Recall that the graph of y = x^2 + 3 was identical to the graph of y = x^2, except that it was raised 3 units. This function is of the form y = x^2 + c. In the case of this specific function, c = 3. What function would this form give us for c = -1? How would the graph of this function compare with the graph of y = x^2?

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RESPONSE -->

confidence assessment:

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21:11:38

If c = -1 the form y = x^2 + c gives us y = x^2 - 1. Every value on a table of this function would be 1 less than the corresponding value on a table of y = x^2, and the graph of y = x^2 - 1 will lie 1 unit lower at each point then the graph of y = x^2.

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RESPONSE -->

self critique assessment:

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21:11:41

`q002. Suppose that we wish to graph the functions y = x^2 + c for c = -3, then for c = -2, then for c = -1, then for c = 0, then for c = 1, then for c = 2, then for c = 3. If all these functions were plotted on the same set of coordinate axes, what would the final graph look like? It is suggested that you actually sketch your graph and describe your sketch.

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RESPONSE -->

confidence assessment:

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֝ܜEĿBղĉfwT~

assignment #006

006.

Precalculus I

02-20-2009

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21:13:10

`q001. Note that this assignment has 10 questions

Recall that the graph of y = x^2 + 3 was identical to the graph of y = x^2, except that it was raised 3 units. This function is of the form y = x^2 + c. In the case of this specific function, c = 3. What function would this form give us for c = -1? How would the graph of this function compare with the graph of y = x^2?

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RESPONSE -->

confidence assessment:

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21:13:12

If c = -1 the form y = x^2 + c gives us y = x^2 - 1. Every value on a table of this function would be 1 less than the corresponding value on a table of y = x^2, and the graph of y = x^2 - 1 will lie 1 unit lower at each point then the graph of y = x^2.

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RESPONSE -->

self critique assessment:

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21:13:14

`q002. Suppose that we wish to graph the functions y = x^2 + c for c = -3, then for c = -2, then for c = -1, then for c = 0, then for c = 1, then for c = 2, then for c = 3. If all these functions were plotted on the same set of coordinate axes, what would the final graph look like? It is suggested that you actually sketch your graph and describe your sketch.

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RESPONSE -->

confidence assessment:

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21:13:17

The graph of the c= -3 function y = x^2 - 3 will lie 3 units lower than the graph of y = x^2.

The graph of the c= -2 function y = x^2 - 2 will lie 22222 units lower than the graph of y = x^2.

The progression should be obvious. The graph of the c= 3 function y = x^2 + 3 will lie 3 units higher than the graph of y = x^2.

The final graph will therefore show a series of 7 functions, with the lowest three units below the parabolic graph of y = x^2 and the highest three units above the graph of this function. Each graph will lie one unit higher than its predecessor.

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RESPONSE -->

self critique assessment:

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21:13:19

`q003. The function y = (x -1)^3 is of the form y = (x -k)^3 with k = 1. What function would this form give us for k = 3? How would the graph of this function compare with that of y = x^3?

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RESPONSE -->

confidence assessment:

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21:13:21

Recall how the graph of y = (x-1)^3 lies one unit to the right of the graph of y = x^3. The k = 3 function y = (x -3)^3 will lie 3 units to the right of the graph of y = x^3.

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RESPONSE -->

self critique assessment:

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21:13:23

`q004. Suppose we wish to graph the functions y = (x -k)^3 for k values 2, then 3, then 4. If we graph all these functions on the same set of coordinate axes, what will the graph look like? It is suggested that you actually sketch your graph and describe your sketch.

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RESPONSE -->

confidence assessment:

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21:13:27

The k = 2 graph will lie 2 units to the right of the graph of y = x^3, and the k = 4 graph will lie 4 units to the right. The three graphs will all have the same shape as the y = x^3 graph, but will lie 2, 3 and 4 units to the right.

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RESPONSE -->

self critique assessment:

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21:17:09

`q005. The function y = 3 * 2^x is of the form y = A * 2^x for A = 3. What function would this form give us for A = 2? How would the graph of this function compare with that of y = 2^x?

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RESPONSE -->

y=3 * 2^x graph is 3 times as far from the x axis as y=2^x and narrower, so y=2 * 2^x is 2 times farther from x axis as y=2^x

confidence assessment: 2

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21:17:17

As we saw earlier, the graph of y = 3 * 2^x lies 3 times as far from the x-axis as a graph of y = 2^x and is at every point three times as steep. We would therefore expect the A = 2 function y = 2 * 2^x to lie 2 times is far from the x-axis as the graph of y = 2^x.

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RESPONSE -->

self critique assessment: 3

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21:20:19

`q006. Suppose we wish to graph the functions y = A * 2^x for values A ranging from 2 to 5. If we graph all such functions on the same set of coordinate axes, what will the final graph look like? It is suggested that you actually sketch your graph and describe your sketch.

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RESPONSE -->

The graphs be 2-5 times farther from the x axis and 2-5 times as steep

confidence assessment: 3

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21:20:47

These graphs will range from 2 times as far to 5 times as far from the x-axis as the graph of y = 2^x, and will be from 2 to 5 times as steep. The y intercepts of these graphs will be (0,2), (0, 3), (0, 4), (0,5).

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RESPONSE -->

should have specified the intercepts

self critique assessment: 3

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21:23:31

`q007. What is the slope of a straight line connecting the points (3, 8) and (9, 12)?

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RESPONSE -->

2/3 you get this by 12-8=4 over 9-3=6 and 4/6 is simplified to 2/3

confidence assessment: 3

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21:23:39

The rise between the points is from y = 8 to y = 12. This is a rise of 12-8 = 4.

The run between these points is from x = 3 to x = 9, a run of 9 - 3 = 6.

The slope between these points is therefore rise/run = 4/6 = 2/3, with decimal equivalent .6666....

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RESPONSE -->

self critique assessment: 3

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21:24:49

`q008. What are the coordinates of the t = 5 and t = 9 points on the graph of y = 2 t^2 + 3? What is the slope of the straight line between these points?

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RESPONSE -->

28

confidence assessment: 3

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21:25:10

The t = 5 value is y = 2 * 5^2 + 3 = 2 * 25 + 3 = 50 + 3 = 53.

The t = 9 value is similarly calculated. We obtain y = 165.

The rise between these points is therefore 165-53 = 112. The run is from t = 5 to t = 9, a run of 9 - 5 = 4. This slope of a straight line connecting these points is therefore rise/run = 112/4 = 28.

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RESPONSE -->

self critique assessment: 3

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21:27:29

`q009. Suppose y = 2 t^2 + 3 represents the depth, in cm, of water in a container at clock time t, in seconds. At what average rate does the depth of water change between t = 5 seconds and t = 9 seconds?

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RESPONSE -->

the answer to this is 28, it is exactly like the previous question which means slope and average rate of the depth of the water are directly related

confidence assessment: 3

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21:28:01

The t = 5 second and t = 9 second depths are easily calculated to be y = 53 cm and y = 165 cm. The depth therefore changes from 53 cm to 165 cm, a change of 165 cm - 53 cm = 112 cm, in the 4 seconds between the to clock times. The average rate of depth changes therefore 112 cm/(4 seconds) = 28 cm/second.

We note that this calculation is identical to the calculation of the slope of the straight line connecting the t = 5 and t = 9 points of the graph y = 2 t^2 + 3.

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RESPONSE -->

self critique assessment: 3

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21:30:13

`q010. If we have a graph of depth y vs. clock time t, then how to we know that the slope of a straight line connecting two points of the graph represents the average rate at which depth changes over the corresponding time interval?

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RESPONSE -->

rise over run equals depth over change so slope and average rate are equal to each other

confidence assessment: 3

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21:30:23

02-20-2009 21:30:23

The rise of the graph represents the change in the depth y and the run represents the change clock time t. The slope, which is rise/run, therefore represents change in depth/change in clock time, which is the average rate at which the depth changes.

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NOTES -------> The rise of the graph represents the change in the depth y and the run represents the change clock time t. The slope, which is rise/run, therefore represents change in depth/change in clock time, which is the average rate at which the depth changes.

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