Continuity and intermediate value theorem

In summary, the conversation discusses a proof regarding a function g on a closed bounded interval [x,y]. It is given that g is continuous and that there exists a number k strictly between g(x) and g(y) such that the preimage of k, denoted as g-1(k), has at least two elements. The goal is to prove that there exists another number m strictly between g(x) and g(y) such that the preimage of m, g-1(m), has at least three elements. The intermediate value theorem is mentioned as a possible approach, but the speaker is having trouble visualizing the situation with just two elements for g-1(k). The conversation ends with the suggestion to
  • #1
saquibaa
2
0
let [x,y] be in R and be a closed bounded interval and let g: [x,y] --> R be a function. suppose g is continuous. let k exist in R. suppose that k is strictly between g(x) and g(y) and that g-1(k) has at least 2 elements. prove that there is some m that is strictly between g(x) and g(y) and that g-1(m) has at least three elements.

i can't visualize this (i.e. with just 2 elements for g-1(k)). i know i need to use intermediate value theorem but can't come up with anything concrete.
 
Physics news on Phys.org
  • #2
please help...
 
  • #3
i can't visualize this (i.e. with just 2 elements for g-1(k))

Start by drawing a picture. Pick where g(x) and g(y) are, and pick two points that have the same y-value in between x and y. Then start drawing a couple of graphs
 

Related to Continuity and intermediate value theorem

1. What is the continuity theorem?

The continuity theorem states that a function is continuous at a point if the limit of the function at that point exists and is equal to the value of the function at that point.

2. What is the intermediate value theorem?

The intermediate value theorem states that if a function is continuous on a closed interval [a,b], then it takes on every value between f(a) and f(b) at least once.

3. How are the continuity and intermediate value theorems related?

The intermediate value theorem is a consequence of the continuity theorem. It relies on the fact that a continuous function takes on all values between two points.

4. Can the continuity and intermediate value theorems be applied to all functions?

No, the continuity and intermediate value theorems only apply to continuous functions. A function is continuous if it has no breaks, holes, or jumps in its graph.

5. What are some real-life applications of the continuity and intermediate value theorems?

The continuity and intermediate value theorems are commonly used in physics, engineering, and economics to model and analyze real-world phenomena. They are also used in computer science, particularly in the field of numerical analysis.

Similar threads

  • Calculus and Beyond Homework Help
Replies
3
Views
559
  • Calculus and Beyond Homework Help
Replies
3
Views
846
  • Calculus and Beyond Homework Help
Replies
2
Views
386
  • Calculus and Beyond Homework Help
Replies
12
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
571
  • Calculus and Beyond Homework Help
Replies
1
Views
608
  • Calculus and Beyond Homework Help
Replies
4
Views
532
  • Calculus and Beyond Homework Help
Replies
14
Views
1K
  • Calculus and Beyond Homework Help
Replies
3
Views
411
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
Back
Top