Apparent indiscrepancy in the average value of phi function

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The discussion centers on the average asymptotics of the Totient function, specifically the discrepancy in its average value. It references a statement from "Introduction to the Theory of Numbers" that claims the average order of the function is ##\frac{6\cdot n}{\pi^2}##. The author questions this by suggesting that the average value should instead be approximately ##\frac{3\cdot n}{\pi^2}## based on their calculations. They clarify the definitions of average order and provide mathematical reasoning to support their argument. This raises important considerations regarding the interpretation of the Totient function's average behavior.
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So, while solving a problem a friend came up with involving the Totient function, I ended up doing a bit of research into the average asymptotics of the function. On page 268 of Introduction to the Theory of Numbers, it's mentioned that "The average of order of ##\phi\left(n\right)## is ##\frac{6\cdot n}{\pi^2}##. More precisely, ##\Phi\left(n\right)=\phi\left(1\right)+\ldots+\phi\left(n\right)=\frac{3\cdot n^2}{\pi^2}+O\left(n\cdot\log\left(n\right)\right)##."

My question is, wouldn't this mean ##\frac{\phi\left(1\right)+\ldots+\phi\left(n\right)}{n}\approx\frac{3\cdot n}{\pi^2}##, so the average value of the phi function up to n would be approximately ##\frac{3\cdot n}{\pi^2}## and not, as previously stated, ##\frac{6\cdot n}{\pi^2}##?
 
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Recall that an arithmetic function ##f## is said to be of the average order of a function ##g## if
$$f(1)+f(2) + \cdots + f(n) \sim g(1) + g(2) + \cdots + g(n)$$
Let ##f(n)=\phi(n)## and ##g(n)=\frac{6n}{\pi^2}##.
Then ##\phi(n)## has average order ##\frac{6n}{\pi^2}## means that
$$\phi(1)+\phi(2)+\cdots+\phi(n)\sim\frac{6}{\pi^2}(1+2+\cdots+n)$$
and ##1+2+\cdots+n\sim\frac{1}{2}n^2##.
 
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Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

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