Prove that the arithmetic mean of two different positive numbers is gr...
**Proof: Arithmetic Mean is Greater than Geometric Mean**
To prove that the arithmetic mean of two different positive numbers is greater than the geometric mean, let's consider two positive numbers, a and b, where a ≠ b.
**Arithmetic Mean**
The arithmetic mean, denoted by AM, is the sum of two numbers divided by 2. Mathematically, it can be expressed as:
AM = (a + b) / 2
**Geometric Mean**
The geometric mean, denoted by GM, is the square root of the product of two numbers. Mathematically, it can be expressed as:
GM = √(a * b)
**Proof by Contradiction**
To prove the statement, let's assume that the arithmetic mean is not greater than the geometric mean. In other words:
AM ≤ GM
Now, let's substitute the expressions for AM and GM:
(a + b) / 2 ≤ √(a * b)
**Squaring Both Sides**
To simplify the inequality, let's square both sides:
(a + b)^2 / 4 ≤ a * b
Expanding the numerator:
(a^2 + 2ab + b^2) / 4 ≤ a * b
Multiplying both sides by 4:
a^2 + 2ab + b^2 ≤ 4ab
**Simplifying the Inequality**
Rearranging the terms:
a^2 + b^2 - 2ab ≤ 0
Factoring the left side:
(a - b)^2 ≤ 0
Since a and b are positive numbers and a ≠ b, (a - b)^2 will always be greater than zero. However, the inequality states that (a - b)^2 is less than or equal to zero, which is a contradiction.
Therefore, our assumption that AM ≤ GM is incorrect.
**Conclusion**
From the contradiction, we can conclude that the arithmetic mean of two different positive numbers is always greater than the geometric mean.
Hence, the proof is complete.
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