Continuity of a Function at x=-3 - Proving c Value

In summary: On the oringinal function when x= -3, the function is undefined. However, if we set f(-3)=-1/9 then the oringinal function will become continuous on x=-3.
  • #1
KevinFan
47
0
(Mentor note: moved from another forum hence no template)

For what value of the constant c is the following function continuous at x = −3?
f(x)=(1/x+1/3)/(x+3) if x≠ -3
f(x)=c if x=-3please provide proof... I am so confused:(
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
KevinFan said:
For what value of the constant c is the following function continuous at x = −3?
f(x)=(1/x+1/3)/(x+3) if x≠ -3
f(x)=c if x=-3please provide proof... I am so confused:(
Please provide the reason of your confusion ...
 
  • #3
fresh_42 said:
Please provide the reason of your confusion ...
I am confused because the second part of the function is just "c" which is a constant does not involve x.
 
  • #4
What happens with ##f(x)## for ##x \neq -3## if you simplify the fractions? Have you tried to draw a graph around ##x = -3##?
 
  • #5
fresh_42 said:
What happens with ##f(x)## for ##x \neq -3## if you simplify the fractions? Have you tried to draw a graph around ##x = -3##?
I have tried to simplfy the function, it is f(x)=1/(3x) and I noticed for the simplfied function, x can be -3
 
  • #6
fresh_42 said:
What happens with ##f(x)## for ##x \neq -3## if you simplify the fractions? Have you tried to draw a graph around ##x = -3##?
oh, is C=1/(3(-3))=-1/9 ??
 
  • #7
And what is ##f(-3)=c## in this version? By the way: ##x=0## is also forbidden in the original definition of ##x##.
 
  • #8
KevinFan said:
oh, is C=1/(3(-3))=-1/9 ??
Yes. So now you have to find an argument, why ##f(x)## becomes continuous if we set ##f(-3)= -\frac{1}{9}##.
 
  • #9
fresh_42 said:
Yes. So now you have to find an argument, why ##f(x)## becomes continuous if we set ##f(-3)= -\frac{1}{9}##.
Many thanks for your help !
 
  • #10
fresh_42 said:
Yes. So now you have to find an argument, why ##f(x)## becomes continuous if we set ##f(-3)= -\frac{1}{9}##.
On the oringinal function when x= -3, the function is undefined. However, if we set f(-3)=-1/9 then the oringinal function will become continuous on x=-3.
I think I understand now, thank you again for your help
 

Related to Continuity of a Function at x=-3 - Proving c Value

1. What does it mean for a function to be continuous at x=-3?

A function is continuous at x=-3 if the limit of the function as x approaches -3 exists and is equal to the value of the function at x=-3. This means that there are no sudden jumps or breaks in the graph of the function at x=-3.

2. How can I prove that a function is continuous at x=-3?

To prove that a function is continuous at x=-3, you must show that the limit of the function as x approaches -3 exists and is equal to the value of the function at x=-3. This can be done using the definition of continuity and various limit theorems.

3. What is the significance of x=-3 in determining continuity of a function?

The value of x=-3 is important because it is the point at which we are evaluating the continuity of the function. In order for a function to be continuous at x=-3, the limit of the function as x approaches -3 must exist and be equal to the value of the function at x=-3.

4. Can a function be continuous at x=-3 but not at other points?

Yes, a function can be continuous at x=-3 but not at other points. This means that the function may have sudden jumps or breaks at other points, but at x=-3, the limit of the function exists and is equal to the value of the function at x=-3.

5. What are some common techniques for proving continuity at x=-3?

Some common techniques for proving continuity at x=-3 include using the definition of continuity, using the limit laws and properties, and using the intermediate value theorem. It is important to carefully analyze the function and its behavior at x=-3 in order to determine the best approach for proving continuity.

Similar threads

  • Precalculus Mathematics Homework Help
Replies
15
Views
814
Replies
19
Views
893
  • Precalculus Mathematics Homework Help
Replies
12
Views
1K
  • Precalculus Mathematics Homework Help
Replies
11
Views
711
Replies
21
Views
714
  • Precalculus Mathematics Homework Help
Replies
7
Views
1K
  • Precalculus Mathematics Homework Help
Replies
2
Views
560
  • Precalculus Mathematics Homework Help
Replies
3
Views
956
  • Precalculus Mathematics Homework Help
Replies
4
Views
1K
  • Precalculus Mathematics Homework Help
Replies
13
Views
483
Back
Top