Finding limits to a piecewise function (3 pieces)

In summary, the limit of a function at a given number is the value that the function approaches as the input approaches that number. In this case, the limit at 1 from both the left and right sides is -2. The value of f(x) at x=1 does not affect the limit, as it only matters what happens as x approaches 1.
  • #1
AllanW
18
0

Homework Statement


f(x)=-2 when x<1
=3 when x=1
=x-3 when x>1
find the limit at 1 from the left and right sides and at 1.

Homework Equations

The Attempt at a Solution


limit for x when approaching 1 from the left is -2
limit for x when approaching 1 from the right is -2
-I'm not sure if the limit at 1 would be -2, or 3
 
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  • #2
You're correct, but perhaps you should go back and read about what it means for a limit to equal a value. Does it matter what happens to the function at the point you're approaching?
 
  • #3
axmls said:
You're correct, but perhaps you should go back and read about what it means for a limit to equal a value. Does it matter what happens to the function at the point you're approaching?
All i need to know is what my limit is at x=1 or if the limit even exists.
 
  • #4
AllanW said:
All i need to know is what my limit is at x=1 or if the limit even exists.
Which you will learn if you follow axmls's suggestion.
axmls said:
perhaps you should go back and read about what it means for a limit to equal a value. Does it matter what happens to the function at the point you're approaching?
The way things work here at PF is that we help you arrive at an answer, but we won't just give it to you.
 
  • #5
Mark44 said:
Which you will learn if you follow axmls's suggestion.

The way things work here at PF is that we help you arrive at an answer, but we won't just give it to you.
Okay, would i be correct if i said the limit for x at 1 would be -2?
 
  • #6
AllanW said:
Okay, would i be correct if i said the limit for x at 1 would be -2?
Yes. Do you understand why?
 
  • #7
Mark44 said:
Yes. Do you understand why?
I believe it because the limits approaching 1 from the left and right side is -2, what i don't understand is if and where the 'f(x)=3 when x=1' comes into play
 
  • #8
AllanW said:
I believe it because the limits approaching 1 from the left and right side is -2, what i don't understand is if and where the 'f(x)=3 when x=1' comes into play
What does your book have for the definition of the limit of a function at some number?
 

1. What is a piecewise function?

A piecewise function is a function that is defined by different equations over different intervals of the input variable. This means that the function has different rules for different parts of its domain.

2. How do you find the limits of a piecewise function?

To find the limits of a piecewise function, you need to evaluate the limits of each piece of the function separately. Then, you can compare the limits to see if they approach the same value. If they do, then that value is the limit of the entire piecewise function.

3. What are the common methods for finding limits of a piecewise function?

The most common methods for finding limits of a piecewise function are: using direct substitution, factoring and simplifying, and using the Squeeze Theorem.

4. Can a piecewise function have an infinite limit?

Yes, a piecewise function can have an infinite limit. This can happen if one of the pieces of the function has an infinite limit or if the limits of the pieces approach different values from each side of the point.

5. How do you determine if a piecewise function is continuous?

A piecewise function is continuous if the function is defined at every point in its domain and if the limits from both sides of each point in the domain are equal. This means that there are no gaps or jumps in the graph of the function.

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