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!

Sequences - factorial r, !

  1. Nov 14, 2003 #1
    Can anybody help me solving this?

    Write in terms of factorials

    n((n^2)-1)

    The correct answer is
    (n+1)!/(n-2)!

    but I don't know how to get there, and since it's week- end I have no chance to ask anyone teachers, etc.
    //Martin
     
  2. jcsd
  3. Nov 14, 2003 #2
    n(n2-1) = n(n-1)(n+1)
     
  4. Nov 14, 2003 #3
     
  5. Nov 14, 2003 #4

    Tom Mattson

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I'll give you a hint.

    Expand the numerator and denominator of the above ratio and cancel the factors common to both. For instance, the numerator is:

    (n+1)!=(n+1)(n)(n-1)(n-2)...

    Get the idea?
     
  6. Nov 14, 2003 #5
    Yes!:smile:
    Thank you!

    //Martin
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Sequences - factorial r, !
  1. R method (Replies: 4)

  2. Solve in R (Replies: 17)

  3. Find a and r (Replies: 5)

  4. R^2 or R^3? (Replies: 3)

Loading...