What Are the Properties of Limits in Mathematics?

  • Thread starter Thread starter nycmathguy
  • Start date Start date
  • Tags Tags
    Limits Properties
Click For Summary

Homework Help Overview

The discussion revolves around the properties of limits in mathematics, specifically focusing on a limit involving the cube root function and its behavior around a particular point. Participants explore the implications of modifying a function at a specific point and how it affects the limit.

Discussion Character

  • Conceptual clarification, Assumption checking, Mixed

Approaches and Questions Raised

  • Participants question the reasoning behind taking the cube root and then cubing the result. There is exploration of how changing the function at a specific point impacts the limit, with some participants suggesting that the limit remains unchanged despite the modification.

Discussion Status

There is an ongoing exploration of the concept of limits, particularly in relation to continuity and discontinuity. Some participants have provided insights into the nature of limits and how they are determined by the behavior of functions around points of interest, while others express confusion about the context of limits in precalculus.

Contextual Notes

Participants note a potential confusion regarding the placement of limits in precalculus materials and question the appropriateness of their inclusion in that context.

nycmathguy
Homework Statement
Determine the limit of f(x) using properties of limits.
Relevant Equations
N/A
See attachment for question and math work.
 

Attachments

  • 1624129320392.png
    1624129320392.png
    7.1 KB · Views: 176
Physics news on Phys.org
You took the cube root of 8 (81/3) and then cubed it. Why?
 
Doc Al said:
You took the cube root of 8 (81/3) and then cubed it. Why?
Let's take it from here:

(1/4)[cr{8}]

(1/4)(2)

1/2

The limit is 1/2.

Why cubed the cube root of 8 in my first attempt?

Answer: typo
 
OK, now you've got it.
 
Yes the limit is 1/2. If we tweak the function and we make it so that f(x) is the same as before for all ##x\neq 8## but we set ##f(8)=256## what will the limit be?
 
Delta2 said:
Yes the limit is 1/2. If we tweak the function and we make it so that f(x) is the same as before for all ##x\neq 8## but we set ##f(8)=256## what will the limit be?
The limit would be 256.
 
  • Sad
Likes   Reactions: Vanadium 50 and PeroK
nycmathguy said:
The limit would be 256.
Nope it will remain 1/2. For the limit we focus what happens around the point of interest but not necessarily onto the point of interest. Around 8 the tweaked function remains the same so the limit remains the same. I just introduced an artificial discontinuity in the tweaked function by setting f(8)=whatever except 1/2.

I guess you need to be introduced to continuity and discontinuity by your textbook. If it is not done by your precalculus book, it should be done by your calculus I book.
 
  • Like
Likes   Reactions: nycmathguy
Delta2 said:
Nope it will remain 1/2. For the limit we focus what happens around the point of interest but not necessarily onto the point of interest. Around 8 the tweaked function remains the same so the limit remains the same. I just introduced an artificial discontinuity in the tweaked function by setting f(8)=whatever except 1/2.

I guess you need to be introduced to continuity and discontinuity by your textbook. If it is not done by your precalculus book, it should be done by your calculus I book.
What are limits doing in a pre-calculus book, one wonders?
 
  • Haha
Likes   Reactions: Delta2
PeroK said:
What are limits doing in a pre-calculus book, one wonders?
The boundaries between calculus and precalculus are fuzzy, at least that's what Ron Larson thinks lol...
 
  • Like
Likes   Reactions: PeroK
  • #10
PeroK said:
What are limits doing in a pre-calculus book, one wonders?
Not in a precalculus book. I made a typo. The limits are in the following book:
 

Attachments

  • Screenshot_20210620-131951_Drive.jpg
    Screenshot_20210620-131951_Drive.jpg
    23.6 KB · Views: 159
  • Like
Likes   Reactions: Delta2

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 20 ·
Replies
20
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K