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Mathematical induction question

  1. Apr 5, 2013 #1
    Hi all,

    I am revising on Proof by mathematical induction and I have came across a question I haven't found a way to work it out.

    [tex]\sum_{r=1}^n r(r!) = (n + 1)! -1[/tex]

    I understand the steps of proving by mathematical induction question. The ! is causing the confusion.
  2. jcsd
  3. Apr 5, 2013 #2


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    2017 Award

    Staff: Mentor

    In which way? It is a Factorial.
  4. Apr 5, 2013 #3


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    Science Advisor

    Maybe you can rewrite the general summand as:

    (r+1)r!-r! and expand the sum, see what happens.
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