Filling in the blank to a statement

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Homework Help Overview

The discussion revolves around determining the largest number that can fill in the blank in the statement regarding the proximity of x to 3 and the behavior of the function f(x) near that point. The subject area includes concepts of limits and continuity in calculus.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the implications of the function's continuity and the nature of the discontinuity at x = 3. Some express uncertainty about the requirements of the problem without a specific function provided, while others question the definitions and assumptions regarding continuity and limits.

Discussion Status

The conversation is ongoing, with participants exploring different interpretations of the function and its properties. Some guidance has been offered regarding the nature of the discontinuity and its implications for the problem, but no consensus has been reached on the correct approach or answer.

Contextual Notes

There is a noted lack of clarity regarding the function f(x) and its behavior at the point of discontinuity, which is central to resolving the problem. The original poster's mention of specific values (1.99 and 2.01) indicates an attempt to relate these to the function's output, but the discussion highlights the need for further clarification on the function itself.

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Homework Statement


For the statement "If x is within _______ units of 3 (but not equal to 3), then f(x) is within 0.01 unit of 2," write the largest number that can go in the blank


Homework Equations


Nonr


The Attempt at a Solution


It's a multi-step problem, but the two numbers I ended up with are 1.99 or 2.01. I'm not sure which one fits into this statement because I'm not quite sure what it's asking.
 
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MellowOne said:

Homework Statement


For the statement "If x is within _______ units of 3 (but not equal to 3), then f(x) is within 0.01 unit of 2," write the largest number that can go in the blank


Homework Equations


Nonr


The Attempt at a Solution


It's a multi-step problem, but the two numbers I ended up with are 1.99 or 2.01. I'm not sure which one fits into this statement because I'm not quite sure what it's asking.
This question doesn't make sense unless you are given a specific function f! It looks to me like f is some continuous function such that f(3)= 2. But what goes in the blank depends upon exactly what f is. Surely you realized that?
 
Sorry, maybe I should have put the function that I was given. I'm not sure what F! means, but here's the function I'm given. F(x) = (x^3 - 7x^2 + 17x - 15)/( x - 3) It is a continuous graph, but at x = 3 there's a point of discontinuity which is (3,2).
 
MellowOne said:
Sorry, maybe I should have put the function that I was given. I'm not sure what F! means, but here's the function I'm given. F(x) = (x^3 - 7x^2 + 17x - 15)/( x - 3) It is a continuous graph, but at x = 3 there's a point of discontinuity which is (3,2).
The exclamation point after f was punctuation in the sentence, just like this one!
The graph can't be continuous AND have a point of discontinuity. Without looking at the graph, I'm guessing that there is a "hole" at (3, 2). I'm also guessing that if you divided the numerator polynomial (x^3 + ...) by (x - 3) there wouldn't be a remainder. That might be a hint.
 
MellowOne said:
Sorry, maybe I should have put the function that I was given. I'm not sure what F! means, but here's the function I'm given. F(x) = (x^3 - 7x^2 + 17x - 15)/( x - 3) It is a continuous graph, but at x = 3 there's a point of discontinuity which is (3,2).
You mean that F has a removable discontinuity at x= 3. That's a discontinuity because 33- 7(32+ 17(3)- 15= 27-63+ 51- 15= 78- 78= 0 as well as 3- 3= 0: both numerator and denominator are 0 at x= 3. Because x= 3 makes the numerator 0, we know that x-3 is a factor. Knowing that it is easy to see that x3- 7x2+ 17x- 15= (x-3)(x2- 4x+ 5) so for x NOT equal to 3, this is just F(x)= x2- 4x+ 5= (x-4)(x-1). The discontinuity is "removable" because that has limit 3 at x= 2.

Now, if "f(x) is within 0.01 unit of 2", that is, if 1.99\le x^2- 4x+ 5\le 2.01 what must x be?
 

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