Asst 8 query

course Mth 271

¶ïoÓƒ|ƙ龨F£û}½³“wѽýû¡åÓ¦|¹Óassignment #008

008. `query 8

Applied Calculus I

10-12-2008

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15:27:40

What functions f(z) and g(t) express the function 2^(3t-5) as a composite f(g(t))?

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RESPONSE -->

f(t) = 2^t

g(t) = 3t - 5

confidence assessment: 2

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15:27:59

CORRECT STUDENT RESPONSE: f(z)=2^z and g(t)=3t-5, so that f(g(t)) = 2^g(t) = 2^(3t-5).

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self critique assessment: 3

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15:32:40

1.3.81 (was 1.3.66 temperature conversion. What linear equation relates Celsius to Fahrenheit?

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RESPONSE -->

I found the slope of the line (212 - 32) / (100 - 0) = 180/100 = 9/5. One of the given points contains the y intercept since C is 0 when F is 32. Writing the equation is slope-intercept form y = mx + b, I get the equation C = (9/5)F + 32

confidence assessment: 3

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15:33:00

CORRECT STUDENT RESPONSE: degrees Fahrenheit=1.8(degrees Celsius)+32, or F = 1.8 C + 32.

INSTRUCTOR COMMENT:

Since each Fahrenheit degree is 1.8 Celsius degrees a graph of F vs. C will have slope 1.8. Since F = 32 when C = 0 the graph will have vertical intercept at (0, 32) so the y = m x + b form will be F = 1.8 C + 32.

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RESPONSE -->

self critique assessment: 3

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15:34:29

How did you use the boiling and freezing point temperatures to get your relationship?

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RESPONSE -->

The boiling and freezing point relationships of C and F were like data points for values x and y. I found the slope by taking (F2 - F1) / (C2 - C1)

confidence assessment: 3

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15:34:49

A graph of Fahrenheit vs. Celsius temperatures gives us the two (x,y) points (o,32) and (100,212).

We use these two points to find the slope m=(y2-y1)/(x2-x1) = (212 - 32) / 100 = 1.8.

Now we insert the coordinates of the point (0,32) and into the point-slope form y = 1.8 x + b of a line to get 32 = 1.8 * 0 + b. We easily solve to get b = 32.

{So the equation is y = 1.8 x + 32, or F = 1.8 C + 32. **

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RESPONSE -->

self critique assessment: 3

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&#Very good responses. Let me know if you have questions. &#