Question:medium

If \( \sum_{k=1}^{n} \varphi(k) = \frac{2\pi (n+1)}{} \), then \( \sum_{k=1}^{10} \frac{1}{\varphi(k)} \) is equal to:

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The Euler’s totient function \( \varphi(k) \) counts the number of positive integers less than or equal to \( k \) that are coprime with \( k \). Remember that for prime numbers \( p \), \( \varphi(p) = p-1 \).

Updated On: Apr 9, 2026

\( \frac{11}{20} \)
220
\( \frac{55}{18} \)
10

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The Correct Option is C

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If \( \sum_{k=1}^{n} \varphi(k) = \frac{2\pi (n+1)}{} \), then \( \sum_{k=1}^{10} \frac{1}{\varphi(k)} \) is equal to:

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The Correct Option is C

Solution and Explanation

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