Find the limit question: Kinda confusing.

In summary: Please try again.Correct, the limit from the left doesn't equal the limit from the right, so the overall limit does not exist.Please try again.
  • #1
nukeman
655
0

Homework Statement



Image here shows the question:

3538hfq.png


Homework Equations





The Attempt at a Solution



I thought the answer would be limit = infinity

I don't understand how to find the limit to this question.
 
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  • #2
nukeman said:

Homework Statement



Image here shows the question:

3538hfq.png


Homework Equations





The Attempt at a Solution



I thought the answer would be limit = infinity

I don't understand how to find the limit to this question.

Try simplifying the expression |4 - x| / (x - 4). Consider two cases separately: x < 4 and x > 4.
 
  • #3
Thats what I did. I got to x < 4 and x > 4

After that, what do I do?
 
  • #4
isnt this undefined?
 
  • #5
nukeman said:
Thats what I did. I got to x < 4 and x > 4

After that, what do I do?

What were your results?

What is |4 - x| / (x - 4) when x < 4?

What is |4 - x| / (x - 4) when x > 4?
 
  • #6
jbunniii said:
What were your results?

What is |4 - x| / (x - 4) when x < 4?

What is |4 - x| / (x - 4) when x > 4?

My results were -1
 
  • #7
nukeman said:
My results were -1

For both cases? If so, the limit would be -1.

However, you made a mistake in one of the cases.
 
  • #8
jbunniii said:
For both cases? If so, the limit would be -1.

However, you made a mistake in one of the cases.

I did?
 
  • #9
nukeman said:
I did?

You did, if you got -1 for both cases.

To see what went wrong, please answer these two questions:

What does |4 - x| simplify to, if x > 4?
What does |4 - x| simplify to, if x < 4?

Your answers shouldn't contain any absolute values.
 
  • #10
What does |4 - x| simplify to, if x > 4?
What does |4 - x| simplify to, if x < 4?

I am sorry, I don't understand :(
 
  • #11
I think what is messing me up is the absolute value bars
 
  • #12
The absolute value function is defined as:

|a| = -a if a<0
|a| = a if a>=0

This is what you have to work with.
 
  • #13
Ahhh...So, then my calc comes out as -1 and 1, therefore it does not equal so its undefined?
 
  • #14
nukeman said:
Ahhh...So, then my calc comes out as -1 and 1, therefore it does not equal so its undefined?

Correct, the limit from the left doesn't equal the limit from the right, so the overall limit does not exist.
 

FAQ: Find the limit question: Kinda confusing.

What is a limit in mathematics?

A limit is a fundamental concept in mathematics that describes the behavior of a function as its input approaches a certain value. It is often used to describe the value that a function approaches as its input gets closer and closer to a specific value.

How do you find the limit of a function?

To find the limit of a function, you can use a variety of methods such as substitution, factoring, and L'Hôpital's rule. You can also use graphical methods, such as graphing the function or using a graphing calculator, to estimate the limit.

What is the difference between a one-sided limit and a two-sided limit?

A one-sided limit only considers the behavior of a function as its input approaches a specific value from one direction, either the left or the right. A two-sided limit considers the behavior of the function as its input approaches the specific value from both the left and the right.

Can a limit not exist?

Yes, a limit may not exist if the function has a vertical asymptote, jumps, or oscillates near the specific value. In these cases, the limit is said to be either undefined or infinite.

How can finding limits be useful in real-world applications?

Finding limits can be useful in real-world applications, such as in physics, engineering, and economics, where it is used to model and predict the behavior of systems and processes. For example, limits are used to determine the velocity and acceleration of an object in motion or to calculate the maximum profit in a business model.

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