1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Help with proof using cases

  1. Mar 10, 2008 #1
    1. The problem statement, all variables and given/known data
    For each integer n, if n is odd then 8[tex]\left|[/tex] (n[tex]^{2}[/tex]-1)

    2. Relevant equations
    Def of an odd number 2q+1

    3. The attempt at a solution

    (2q+1)[tex]^{2}[/tex] -1
    4q[tex]^{2}[/tex] +4q+1-1
    4q[tex]^{2}[/tex] +4q
    Here is where I get stuck.... should I factor out the 4 and say that q[tex]^{2}[/tex] +q is an integer and therefore can be wrote as some integer r and therefore 8[tex]\left|[/tex] 4r?
  2. jcsd
  3. Mar 10, 2008 #2


    User Avatar
    Science Advisor
    Homework Helper

    Can you show q^2+q is divisible by 2 for any integer q? If so, then 4q^2+4q is divisible by 8.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Help with proof using cases
  1. Even/odd case proof (Replies: 1)