1. Limited time only! Sign up for a free 30min personal 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!

Factorial Question

  1. Jan 31, 2016 #1
    How do you get

    (n + 1)! = (n + 1)(n)(n - 1)(n - 2) ... 3 ⋅ 2 ⋅ 1

    ????

    Isn't (n + 1)! = (n + 1) ⋅ (n + 1 - 1) ⋅ (n + 1 - 2) ⋅ (n + 1 - 3) ⋅ (n + 1 - 4) ... and so on?
     
  2. jcsd
  3. Jan 31, 2016 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    You need to realise that:
    n+1-1 = n
    n+1-2 = n-1
    n+1-3 = n-2
    etc
     
  4. Jan 31, 2016 #3

    jedishrfu

    Staff: Mentor

    or more compactly:

    (n+1)! = (n+1) * (n+1-1)! = (n+1) * n!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...