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Sunday, February 13, 2022

2022/022) Find all solutions in positive integers x, y, z of the equation \frac{x}{y} + \frac{y}{z} + \frac{z}{x} = 3

We have by AM GM inequaity among \frac{x}{y} ,\frac{y}{z}, \frac{z}{x}

we have 

\frac{\frac{x}{y} + \frac{y}{z} + \frac{z}{x}}{3} >= \sqrt[2]{\frac{x}{y} * \frac{y}{z} * \frac{z}{x}}

 or  \frac{\frac{x}{y} + \frac{y}{z} + \frac{z}{x}}{3} >= \sqrt[2]{1}

or  \frac{x}{y} + \frac{y}{z} + \frac{z}{x}>=  3

this is greater than 3 if all are not equal and is 3 if all are equal

or  \frac{x}{y} = \frac{y}{z} = \frac{z}{x}

or x = y = z (any integer)  


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