Finding delta in terms of epsilon-delta definition

Click For Summary

Homework Help Overview

The discussion revolves around the epsilon-delta definition of limits in calculus, specifically focusing on finding a delta (δ) in relation to a given epsilon (ε) for the function f(x) = 3x + 1 at the point x = 1.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants examine the relationship between δ and ε, with one participant attempting to derive δ based on the condition |f(x) - f(1)| < ε. There is a focus on whether the derived δ = ε/3 is valid and if the approach taken is correct.

Discussion Status

Some participants affirm the correctness of the solution provided, while others suggest that the original poster could have framed their question differently to reflect their uncertainty. The conversation indicates a supportive environment, with acknowledgment of the challenges faced in building self-confidence in mathematical reasoning.

Contextual Notes

There is an underlying theme of personal struggle with self-confidence affecting the approach to problem-solving in mathematics. Participants are navigating both the mathematical concepts and the emotional aspects of learning.

Bolz
Messages
8
Reaction score
0

Homework Statement



If f(x) = 3x+1 en assume δ > 0. Assume ε>0.
Give a δ > 0 with the following property :

|x-1|< δ => |f(x) - f(1)| < ε

Homework Equations





The Attempt at a Solution




|f(x) - f(1)| < ε
<=> |3x+1-(3*1+1)| < ε
<=> |3x-3| < ε
<=> |x-1| < ε/3


|x-1| < δ
|x-1| < ε/3


=> δ=ε/3>0


What am I doing wrong?

Thanks in advance!
 
Physics news on Phys.org
Bolz said:

Homework Statement



If f(x) = 3x+1 en assume δ > 0. Assume ε>0.
Give a δ > 0 with the following property :

|x-1|< δ => |f(x) - f(1)| < ε

Homework Equations





The Attempt at a Solution




|f(x) - f(1)| < ε
<=> |3x+1-(3*1+1)| < ε
<=> |3x-3| < ε
<=> |x-1| < ε/3


|x-1| < δ
|x-1| < ε/3


=> δ=ε/3>0


What am I doing wrong?

Nothing. Your solution is correct.
 
  • Like
Likes   Reactions: 1 person
pasmith said:
Nothing. Your solution is correct.

Oh ok. I'm learning this on my own so I assumed it had to be wrong. Self confidence is important in math too apparently..
Anyway, thanks for checking it! :)
 
Then it would have been better to ask "Is this correct" rather than "What am I doing wrong"! You are not going to do very well assuming that you cannot do the work.
 
  • Like
Likes   Reactions: 1 person
HallsofIvy said:
Then it would have been better to ask "Is this correct" rather than "What am I doing wrong"! You are not going to do very well assuming that you cannot do the work.


Sorry, you're right. I'm just struggling with a lot in life and I think my lack of self confidence leaked into doing math. Sorry again.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
Replies
7
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 20 ·
Replies
20
Views
3K
Replies
9
Views
4K
  • · Replies 22 ·
Replies
22
Views
4K
  • · Replies 10 ·
Replies
10
Views
3K