# What is bounded above and bounded below?

## What is bounded above and bounded below?

Being bounded from above means that there is a horizontal line such that the graph of the function lies below this line. Bounded from below means that the graph lies above some horizontal line. Being bounded means that one can enclose the whole graph between two horizontal lines.

## Can a set be bounded above and below?

Q.E.D. A set which is bounded above and bounded below is called bounded. So if S is a bounded set then there are two numbers, m and M so that m ≤ x ≤ M for any x ∈ S. Examples of unbounded sets: (−2,+∞),(−∞,3), the set of all real num- bers (−∞,+∞), the set of all natural numbers.

How do you tell if a set is bounded above or below?

A set is bounded above by the number A if the number A is higher than or equal to all elements of the set. A set is bounded below by the number B if the number B is lower than or equal to all elements of the set.

### What is bounded above set?

A set S of real numbers is called bounded from above if there exists some real number k (not necessarily in S) such that k ≥ s for all s in S. The number k is called an upper bound of S. The terms bounded from below and lower bound are similarly defined. A set S is bounded if it has both upper and lower bounds.

### What does it mean if a function is bounded below?

Definition: A function f is bounded below if there is some number b that is less than or equal to every number in the range of f. Answers is in terms of y-values. Any such number b is called a lower bound of f.

What is a bounded function with example?

Some commonly used examples of bounded functions are: sinx , cosx , tan−1x , 11+ex and 11+x2 . All these functions are bounded functions. Note: The graph of a bounded function stays within the horizontal axis, while the graph of unbounded function does not.

## Can a set be bounded by infinity?

You can think of it in the following way. Any set, all of whose elements lie between (for example) 0 and 1, is bounded, because no part of the set can possibly “go to infinity”. But clearly it is possible to have an infinite number of elements in such a set.

What is strictly bounded function?

In mathematics, a function f defined on some set X with real or complex values is called bounded if the set of its values is bounded. In other words, there exists a real number M such that. for all x in X. A function that is not bounded is said to be unbounded.

### How do you check if a set is bounded?

Similarly, A is bounded from below if there exists m ∈ R, called a lower bound of A, such that x ≥ m for every x ∈ A. A set is bounded if it is bounded both from above and below. The supremum of a set is its least upper bound and the infimum is its greatest upper bound.

### How do you prove an upper bound?

An upper bound which actually belongs to the set is called a maximum. Proving that a certain number M is the LUB of a set S is often done in two steps: (1) Prove that M is an upper bound for S–i.e. show that M ≥ s for all s ∈ S. (2) Prove that M is the least upper bound for S.