# Talk:Euler's totient function

 AoPSWiki Article of the Day Euler's totient function was the AoPSWiki Article of the Day for January 30th, 2008

Some motivation and derivation of the formula would make this article more useful.--MCrawford 13:18, 20 June 2006 (EDT)

I changed the part under "Notation". It surely is not best as it is now, but the old one was surely wrong:

- $\phi$ is _not_ a capital letter "Phi", but still a lower case character; compare: $\Phi$ to $\phi$.

- $\varphi$ is about as widely spread as $\phi$, e.g. the normal Wikipedia and more than half of my books prefer $\varphi$. --ZetaX 10:58, 30 January 2008 (EST)

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