Proving Inequality for Natural Numbers n>2

In summary, the conversation discusses a proof for the inequality \prod_{k=1}^{n}\frac{k^{2}+2}{k^{2}+1}<3 and \prod_{k=1}^{n}\frac{k^{2}+2}{k^{2}+1}<\frac{3n}{n+1} for n>2 and n is a natural number. Different approaches such as splitting the product and using induction were attempted, but the most promising result was bounding the product as the exponential of a sum, and then using an integral.
  • #1
gop
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Homework Statement



Proof that for n>2 and n is a natural number it holds that

[tex]\prod_{k=1}^{n}\frac{k^{2}+2}{k^{2}+1}<3[/tex]

and
[tex]\prod_{k=1}^{n}\frac{k^{2}+2}{k^{2}+1}<\frac{3n}{n+1}[/tex]

Homework Equations





The Attempt at a Solution



My best approach was to split the product over the fraction and then to arrive at a statement that looks like

[tex]\prod_{k=2}^{n}k^{2}+2<\prod_{k=1}^{n}k^{2}+1[/tex]

I then tried to prove by induction that this statement holds but that doesn't really work. The best result I got (for n+1) is then

[tex](\prod_{k=2}^{n}k^{2}+2)<(\prod_{k=1}^{n}k^{2}+1)\cdot\frac{n^{2}+2n+2}{n^{2}+2n+3}[/tex]

But I can't do anything usefuel with that...
 
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  • #2
You could try writing the product as the exponential of a sum, and then bounding the sum by an integral.
 

FAQ: Proving Inequality for Natural Numbers n>2

What is the definition of inequality in mathematics?

In mathematics, inequality refers to a relation between two quantities or values that are not equal. It is denoted by symbols such as <, >, ≤, and ≥.

Why is it important to prove inequalities for natural numbers n>2?

Proving inequalities for natural numbers n>2 is important because it allows us to establish the relationship between two quantities and determine which one is larger or smaller. This is useful in solving various mathematical problems and making comparisons.

What are the common methods used to prove inequalities for natural numbers n>2?

The most common methods used to prove inequalities for natural numbers n>2 are induction, contradiction, and direct proof. Induction involves proving the inequality for a base case, and then using a step-by-step process to show that it holds for all values of n. Contradiction involves assuming the opposite of what we want to prove and showing that it leads to a contradiction. Direct proof involves starting with the given information and using logical steps to arrive at the desired conclusion.

Can inequalities for natural numbers n>2 be proven using algebraic manipulations?

Yes, inequalities for natural numbers n>2 can be proven using algebraic manipulations. This involves manipulating the given expressions using algebraic properties such as commutativity, associativity, and distributivity to arrive at the desired inequality.

What are some real-life applications of proving inequalities for natural numbers n>2?

Proving inequalities for natural numbers n>2 has various real-life applications, including in economics, statistics, and computer science. For example, in economics, proving inequalities helps in analyzing market trends and making predictions. In statistics, it is used to compare data sets and determine significant differences. In computer science, it is used in algorithm design and optimization problems.

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