Can You Prove This Inequality for Positive Real Numbers a,b,c,d with Sum of 1?

  • Context: Graduate 
  • Thread starter Thread starter wnvl
  • Start date Start date
  • Tags Tags
    Inequality
Click For Summary
SUMMARY

The inequality to be proven is \(( a+\frac{1}{b})(b+\frac{1}{c})(c+\frac{1}{a}) \geq \left(\frac{10}{3}\right)^3\) for positive real numbers \(a, b, c, d\) such that \(a+b+c+d=1\). The discussion emphasizes the importance of manipulating the given conditions and applying known inequalities such as AM-GM (Arithmetic Mean-Geometric Mean) to establish the proof. Participants suggest starting with substitutions and exploring the implications of the constraint \(a+b+c < 1\).

PREREQUISITES
  • Understanding of inequalities, specifically AM-GM inequality.
  • Familiarity with algebraic manipulation of expressions involving real numbers.
  • Knowledge of positive real number properties.
  • Basic experience with mathematical proofs and logical reasoning.
NEXT STEPS
  • Study the AM-GM inequality and its applications in proving mathematical statements.
  • Explore techniques for manipulating inequalities involving sums and products of variables.
  • Learn about symmetric sums and their role in inequalities.
  • Investigate other inequalities related to positive real numbers, such as Cauchy-Schwarz and Jensen's inequality.
USEFUL FOR

Mathematicians, students in advanced algebra, and anyone interested in inequality proofs and mathematical reasoning involving positive real numbers.

wnvl
Messages
8
Reaction score
0
[tex]a,b,c,d\in\mathbb{R^{+}}\;\;,a+b+c+d=1.[/tex]

Then prove that

[tex]\left( a+\dfrac{1}{b}\right).\left(b+\dfrac{1}{c}\right).\left(c+\dfrac{1}{a}\right)\geq \left(\dfrac{10}{3}\right)^3[/tex]

Anyone an idea on how to start with this exercise?
 
Physics news on Phys.org
wnvl said:
[tex]a,b,c,d\in\mathbb{R^{+}}\;\;,a+b+c+d=1.[/tex]

implies 0<a+b+c<1
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 61 ·
3
Replies
61
Views
10K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
6
Views
2K