Proving the Divisibility of 8 and Odd Squares

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SUMMARY

The discussion focuses on proving that for any positive odd integer n, the expression 8 divides (n² - 1). The participant defines an odd integer as n = 2k + 1 and expands the expression to (2k + 1)² - 1. The conversation highlights the need for a clear approach, suggesting that mathematical induction may not be the most effective method. Instead, alternative strategies, such as those proposed by user phyzguy, are encouraged for a more straightforward proof.

PREREQUISITES
  • Understanding of odd integers and their representation (n = 2k + 1)
  • Basic algebraic expansion techniques
  • Familiarity with divisibility rules, specifically for the number 8
  • Knowledge of mathematical induction principles
NEXT STEPS
  • Explore algebraic proofs involving divisibility by 8
  • Learn about alternative proof techniques beyond mathematical induction
  • Study the properties of odd and even integers in number theory
  • Investigate the implications of the expression (n² - 1) in modular arithmetic
USEFUL FOR

Students studying number theory, mathematicians interested in divisibility proofs, and educators seeking to enhance their teaching methods in algebraic concepts.

PennState666
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Prime Division HELP!

Homework Statement



I need to be able to understand and likely prove that for any positive odd integer n,
8 | (n^2 -1 )

Homework Equations





The Attempt at a Solution


odd can be said to be n = 2k +1
so 8 | (2k + 1)^2 -1
 
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Keep going. Now expand out (2k+1)^2 - 1 and collect terms. Then think about the terms in k and k+1.
 


I got stumped trying mathematical induction i was hoping for a new approach
 


Try the approach that phyzguy is suggesting.
 

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