Euler Phi Function of 148
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Example of Use of Euler $\phi$ Function
- $\map \phi {148} = 72$
where $\phi$ denotes the Euler $\phi$ Function.
Proof
From Euler Phi Function of Integer:
- $\ds \map \phi n = n \prod_{p \mathop \divides n} \paren {1 - \frac 1 p}$
where $p \divides n$ denotes the primes which divide $n$.
We have that:
- $148 = 2^2 \times 37$
Thus:
\(\ds \map \phi {148}\) | \(=\) | \(\ds 148 \paren {1 - \dfrac 1 2} \paren {1 - \dfrac 1 {37} }\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 148 \times \frac 1 2 \times \frac {36} {37}\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 2 \times 1 \times 36\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 72\) |
$\blacksquare$