Finding Supremums and Infimums for Real Numbers | Homework

  • Thread starter Thread starter kmeado07
  • Start date Start date
Click For Summary
SUMMARY

The discussion focuses on proving the formulas for the supremum and infimum of two real numbers, x and y. It establishes that the supremum is given by the formula sup{x,y} = 1/2(x + y + |x - y|) and the infimum by inf{x,y} = 1/2(x + y - |x - y|). The proof involves recognizing that the supremum is the greater of the two numbers and the infimum is the lesser, leading to the simplification of the right-hand sides of the equations.

PREREQUISITES
  • Understanding of real numbers and their properties
  • Familiarity with the concepts of supremum and infimum
  • Basic knowledge of absolute values
  • Ability to manipulate algebraic expressions
NEXT STEPS
  • Study the properties of supremum and infimum in more complex sets
  • Learn about the completeness property of real numbers
  • Explore applications of supremum and infimum in optimization problems
  • Investigate the relationship between supremum, infimum, and limits in calculus
USEFUL FOR

Students studying real analysis, mathematicians interested in order theory, and anyone looking to deepen their understanding of bounds in mathematical contexts.

kmeado07
Messages
40
Reaction score
0

Homework Statement



Show that for all x,y in R (real numbers), sup{x,y}=1/2(x+Y+|X-Y|), and inf{x,y}=1/2(X+Y-|x-y|)


Homework Equations





The Attempt at a Solution



i know that the supremum is the lowest upper bound and that the infimum is the largest lower bound. However i really don't know how to apply that to solving this question.
 
Physics news on Phys.org
If you have two numbers, one has to be at least as big (greater-than-or-equal-to) the other. Assume that x \le y. Then

\sup\{x,y\} = y <br />

and

\inf\{x,y\} = <br /> x


What do the two right-hand-sides simplify to?
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
9K
Replies
6
Views
3K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 5 ·
Replies
5
Views
6K
Replies
3
Views
2K