Math Help Forum: Find the limit if it exists

In summary, the conversation is about understanding limits from a graph and finding if the limit exists or not. The person is struggling to understand the concept and is seeking help. They also mention difficulties with reading the little + and - symbols on the graph and ask for higher resolution. The conversation also touches on the difference between limits as x approaches -2 and x approaches 2, and includes a list of the limits mentioned in the graph. Overall, the person is looking for clarification and explanation on their homework answers.
  • #1
calculus123
4
0
I'm having a really difficult time understanding limits from the graph. I don't completely understand how to find if the limit exists or not. I tried to do these for my homework but I don't know if they are right. Could someone please help me understand limits?
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  • #2
I'm having trouble reading the little + and - symbols in your limits. Is there any way you can display this at a higher resolution?

[edit] just noticed that in b and c, the limits are as x approaches -2, whereas in d and e, x approaches 2.

The first one that looks wrong is b. Is that the limit as x approaches -2 from the positive side? If so, the answer is not 1. To answer this question, ignore everything to the left of x = -2, and ignore what happens at x = -2 itself. Focus only on what the graph is doing as x approaches -2 from the right side. What number is the graph approaching?
 
  • #3
B and C are -2, whereas D and E are +2. Going blind looking at it.
 
  • #4
The limits appear to be:
\begin{align*}
\lim_{x \to -3} f(x) \\
\lim_{x \to -2^+} f(x) \\
\lim_{x \to -2^-} f(x) \\
\lim_{x \to 2^+} f(x) \\
\lim_{x \to 2^-} f(x) \\
\lim_{x \to 4^-} f(x) \\
\lim_{x \to 4^+} f(x) \\
\lim_{x \to 6^+} f(x)
\end{align*}
 
  • #5
calculus123 said:
I'm having a really difficult time understanding limits from the graph. I don't completely understand how to find if the limit exists or not. I tried to do these for my homework but I don't know if they are right. Could someone please help me understand limits?
Explain how you arrived at your answers, so we can see where you're going wrong.
 

Related to Math Help Forum: Find the limit if it exists

What is a limit in math?

A limit in math refers to the value that a function approaches as the input values get closer and closer to a particular value. It is used to analyze the behavior of a function near a specific point and is denoted by the symbol "lim".

How do you find the limit of a function?

To find the limit of a function, you can use various methods such as substitution, factoring, and the use of limit laws. Depending on the type of function, you may also need to use more advanced techniques such as L'Hospital's rule or the Squeeze theorem.

What is a one-sided limit?

A one-sided limit is a limit that is approached from only one direction, either from the left or the right. This is used when the function has a different value or is undefined from each side of the point being evaluated.

Can a limit not exist?

Yes, a limit may not exist if the function does not approach a finite value or if it has different values from each side of the point being evaluated. This can also occur when the function has an infinite or oscillating behavior at the point being evaluated.

Why is finding limits important in mathematics?

Finding limits is important in mathematics because it allows us to understand the behavior of a function and make predictions about its values. It is also essential in calculus, where limits are used to define derivatives and integrals, which are foundational concepts in many fields of science and engineering.

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