Rational numbers - periodic decimal expansion

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SUMMARY

The discussion centers on the periodic decimal expansion of positive rational numbers expressed as n/m in lowest terms. It establishes that the decimal expansion is eventually periodic and that the length of the period divides φ(m), where φ denotes Euler's totient function. The condition (m, 10) = 1 indicates that m and 10 are coprime, which is crucial for determining the nature of the decimal expansion.

PREREQUISITES
  • Understanding of rational numbers and their properties
  • Familiarity with the long division algorithm
  • Knowledge of Euler's totient function, φ(m)
  • Basic concepts of coprime numbers
NEXT STEPS
  • Study the long division algorithm in detail
  • Learn about Euler's totient function and its applications
  • Explore the properties of periodic decimal expansions
  • Investigate the implications of coprimality in number theory
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Mathematics students, educators, and anyone interested in number theory and the properties of rational numbers.

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Homework Statement



Let n/m be a positive rational number in lowest terms. By examining the long division algorithm, show that the decimal expansion of n/m is eventually periodic, and that the period divides phi(m). For simplicity,you may assume that (m, 10) = 1.

Homework Equations



see above

The Attempt at a Solution



Can someone explain what the question means by (m, 10) = 1
 
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I'm not sure what notation your book is using, but from the context, I assume (m, 10) = 1 means that the greatest common divisor of m and 10 is 1; ie., m and 10 are coprime.
 

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