Finding removable and jump discontinuities

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In summary, the conversation discusses finding the values of b that would result in a removable discontinuity or a finite jump discontinuity for the given function. To find the values for a removable discontinuity at 2, the limit as x approaches 2 from below and the limit as x approaches 2 from above must be equal. For a jump discontinuity at 2, the limit from above and below must be different. The limits as x approaches 2 are -20/(2-b)+1 and 5, respectively.
  • #1
DanielJackins
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Homework Statement



f(x) = -x + b, if x < 2
= 5, if x = 2
= -20/(x-b) + 1, if x > 2

For what value(s) of b does f have a removable discontinuity at 2?
For what value(s) of b does f have a (finite) jump discontinuity at 2? Write your answer in interval notation.

The Attempt at a Solution



I'm completely stumped on the removable discontinuity, because I thought you had to be able to cancel out the bottom?

And I'm not sure how to find a jump discontinuity.
 
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  • #2
A removable discontinuity is a value of b where the limit as x->2 from below and the limit as x->2 from above are equal. Your first job is to find those two limits in terms of b. Then equate them. Can you do that?
 
  • #3
Are the limits not -inf and inf?
 
  • #4
DanielJackins said:
Are the limits not -inf and inf?

No. The limits as x->2! The limit from above is (x>2) is -20/(2-b)+1, isn't it? What's the limit from below?
 

Related to Finding removable and jump discontinuities

1. What is a removable discontinuity?

A removable discontinuity, also known as a point discontinuity, occurs when a function has a hole at a specific point. This means that the function is undefined at that point, but can be made continuous by simply filling in the hole with a single point.

2. How can I identify a removable discontinuity?

To identify a removable discontinuity, you can look for a point on the graph where the function is undefined, but there is no jump or break in the graph. This indicates that there is a hole at that point, making it a removable discontinuity.

3. What causes a removable discontinuity?

Removable discontinuities can be caused by factors such as division by zero or the presence of a radical expression in the denominator of a rational function. These factors result in an undefined value at a particular point, creating a hole in the graph.

4. How do I find the limit at a removable discontinuity?

The limit at a removable discontinuity can be found by evaluating the function at the point where the hole is located. This will give you the value of the limit, which is the same from both the left and right sides of the hole.

5. Can a removable discontinuity be removed?

Yes, a removable discontinuity can be removed by filling in the hole at the specific point with a single point. This will make the function continuous at that point and remove the discontinuity.

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