11 part 2

course Mth 271

^䚗\UզКassignment #011

011. `query 11

Applied Calculus I

07-28-2008

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assignment #011

011. `query 11

Applied Calculus I

07-28-2008

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11:33:14

1.6.16 (was 1.6.14 intervals of cont for (x-3)/(x^2-9)

What are the intervals of continuity for the given function?

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RESPONSE -->

continuous on the intervals of (-~,0) (0, ~)

confidence assessment: 1

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11:34:48

The function is undefined where x^2 - 9 = 0, since division by zero is undefined.

x^2 - 9 = 0 when x^2 = 9, i.e., when x = +-3.

So the function is continuous on the intervals (-infinity, -3), (-3, 3) and (3, infinity).

The expression (x - 3) / (x^2 - 9) can be simplified. Factoring the denominator we get

(x - 3) / [ (x - 3) ( x + 3) ] = 1 / (x + 3).

This 'removes' the discontinuity at x = +3. However in the given fom (x-3) / (x^2 + 9) there is a discontinuity at x = -3. **

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RESPONSE -->

self critique assessment: 1

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11:35:23

1.6.24 (was 1.6.22 intervals of cont for |x-2|+3, x<0; x+5, x>=0

What are the intervals of continuity for the given function?

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RESPONSE -->

confidence assessment: 1

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11:36:19

The graph of y = |x-2|+3 is translated 2 units in the x direction and 3 in the y direction from the graph of y = |x|. It forms a V with vertex at (2, 3).

The given function follows this graph up to x = 0. It has slope -1 and y-intercept at y = | 0 - 2 | + 3 = 5.

The graph then follows y = x + 5 for all positive x. y = x + 5 has y-intercept at y = 5. From that point the graph increases along a straight line with slope 1.

So the graph of the given function also forms a V with vertex at (0, 5).

Both functions are continuous up to that point, and both continuously approach that point. So the function is everywhere continuous. **

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RESPONSE -->

self critique assessment: 1

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You need to self-critique.

&#When you do not answer a question you need to continue in your self-critique with a phrase-by-phrase analysis of the solution, detailing everything you do and do not understand. Specific questions are encouraged if you do not understand everything.

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