Assignment 6

course Mth 163

assignment #006006.

Precalculus I

09-24-2008

......!!!!!!!!...................................

16:51:02

`questionNumber 60000

`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?

......!!!!!!!!...................................

RESPONSE -->

The graph will be one lower than y=x^2

confidence assessment: 2

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

......!!!!!!!!...................................

16:51:12

`questionNumber 60000

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.

......!!!!!!!!...................................

RESPONSE -->

i get it

self critique assessment: 2

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

......!!!!!!!!...................................

16:51:42

`questionNumber 60000

`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.

......!!!!!!!!...................................

RESPONSE -->

The final graph would consist of all parabolas raised on point each on the y axis.

confidence assessment: 2

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

......!!!!!!!!...................................

16:51:50

`questionNumber 60000

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.

......!!!!!!!!...................................

RESPONSE -->

i see

self critique assessment: 2

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

......!!!!!!!!...................................

16:52:30

`questionNumber 60000

`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?

......!!!!!!!!...................................

RESPONSE -->

y=(x-3)^3

It will be three spaces to right of original y=x^3 graph

confidence assessment: 2

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

......!!!!!!!!...................................

16:52:38

`questionNumber 60000

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.

......!!!!!!!!...................................

RESPONSE -->

i get it

self critique assessment: 2

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

......!!!!!!!!...................................

16:52:57

`questionNumber 60000

`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.

......!!!!!!!!...................................

RESPONSE -->

Each line will proceed to be one unit to right from last.

confidence assessment: 2

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

......!!!!!!!!...................................

16:53:12

`questionNumber 60000

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.

......!!!!!!!!...................................

RESPONSE -->

I understand how the solution was achieved.

self critique assessment: 2

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

......!!!!!!!!...................................

16:53:39

`questionNumber 60000

`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?

......!!!!!!!!...................................

RESPONSE -->

y=2*2^x

the graph will be 2 times farther from x axis

confidence assessment: 2

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

......!!!!!!!!...................................

16:53:49

`questionNumber 60000

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.

......!!!!!!!!...................................

RESPONSE -->

i think i get it.

self critique assessment: 2

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

......!!!!!!!!...................................

16:54:31

`questionNumber 60000

`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.

......!!!!!!!!...................................

RESPONSE -->

The graph will range from 2 times, 3 times, 4 times, and 5 times farther away from the x axis with each line being 1 unit from the last.

confidence assessment: 2

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

......!!!!!!!!...................................

16:54:42

`questionNumber 60000

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).

......!!!!!!!!...................................

RESPONSE -->

I get it.

self critique assessment: 2

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

......!!!!!!!!...................................

16:55:24

`questionNumber 60000

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

......!!!!!!!!...................................

RESPONSE -->

Find rise by subtracting 8 from 12=4

Find run by subtracting 3 from 9=6

Slope=4/6=2/3

confidence assessment: 2

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

......!!!!!!!!...................................

16:55:32

`questionNumber 60000

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....

......!!!!!!!!...................................

RESPONSE -->

get it

self critique assessment: 2

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

......!!!!!!!!...................................

16:56:45

`questionNumber 60000

`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?

......!!!!!!!!...................................

RESPONSE -->

y=2(5)^2+3=53

y=2(9)^2+3=165

Find rise by subtracting 53 from 165=112=rise

run=9-5=4 112/4=28=slope

confidence assessment: 2

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

......!!!!!!!!...................................

16:56:53

`questionNumber 60000

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.

......!!!!!!!!...................................

RESPONSE -->

got it

self critique assessment: 3

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

......!!!!!!!!...................................

16:58:09

`questionNumber 60000

`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?

......!!!!!!!!...................................

RESPONSE -->

rate=change in depth/change in clock time

Last answer had values for depth y=53 & 165

Subtract 165-53=112/

9-5 gives clocktime=4=28.

confidence assessment: 2

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

......!!!!!!!!...................................

16:58:16

`questionNumber 60000

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.

......!!!!!!!!...................................

RESPONSE -->

i see

self critique assessment: 3

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

......!!!!!!!!...................................

16:58:41

`questionNumber 60000

`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?

......!!!!!!!!...................................

RESPONSE -->

They are both showing slope and depth vs. clock time

confidence assessment: 2

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

......!!!!!!!!...................................

16:58:50

`questionNumber 60000

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.

......!!!!!!!!...................................

RESPONSE -->

ok

self critique assessment: 2

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

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