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# Relationship between AM, GM and HM #### May 27, 2023

To derive the relationship between the Arithmetic Mean (AM), Geometric Mean (GM), and Harmonic Mean (HM) for a set of positive numbers, we can use algebraic reasoning and properties. Let’s assume we have a set of n positive numbers: x₁, x₂, x₃, …, xₙ.

1. Arithmetic Mean (AM):
The Arithmetic Mean is calculated by summing all the values in the set and dividing by the total count, n.

AM = (x₁ + x₂ + x₃ + … + xₙ) / n

2. Geometric Mean (GM):
The Geometric Mean is calculated by taking the nth root of the product of all the values in the set.

GM = (x₁ * x₂ * x₃ * … * xₙ)^(1/n)

3. Harmonic Mean (HM):
The Harmonic Mean is calculated by taking the reciprocal of the arithmetic mean of the reciprocals of all the values in the set.

HM = n / ((1/x₁) + (1/x₂) + (1/x₃) + … + (1/xₙ))

To derive the relationship between these means, we can start by considering the following inequality:

AM ≥ GM

Now, substitute the formulas for AM and GM:

(x₁ + x₂ + x₃ + … + xₙ) / n ≥ (x₁ * x₂ * x₃ * … * xₙ)^(1/n)

Raise both sides to the power of n:

(x₁ + x₂ + x₃ + … + xₙ) ≥ (x₁ * x₂ * x₃ * … * xₙ)

This inequality states that the sum of the values is greater than or equal to the product of the values.

Now, consider the following inequality:

HM ≥ GM

Substitute the formulas for HM and GM:

n / ((1/x₁) + (1/x₂) + (1/x₃) + … + (1/xₙ)) ≥ (x₁ * x₂ * x₃ * … * xₙ)^(1/n)

Raise both sides to the power of n:

n ≥ ((1/x₁) + (1/x₂) + (1/x₃) + … + (1/xₙ))^n

This inequality states that n is greater than or equal to the reciprocal of the arithmetic mean of the reciprocals of the values, raised to the power of n.

Thus, we have derived the relationships:

AM ≥ GM and HM ≥ GM

These inequalities show that the Arithmetic Mean is greater than or equal to the Geometric Mean, and the Harmonic Mean is greater than or equal to the Geometric Mean for a set of positive numbers.