Results 1 to 4 of 4

Math Help - Standard notation

  1. #1
    Member courteous's Avatar
    Joined
    Aug 2008
    From
    big slice of heaven
    Posts
    206

    Question Standard notation

    Are these below a "standard" (i.e. not-obscure) piece one can see in textbooks:

    n_{(r)}=\frac{n^{(r)}}{r!} [ n_{(3)}=\frac{n(n-1)(n-2)}{3!}] and n_{r}=\frac{n^r}{r!}

    ( n!!, I presume, is "standard".)

    Pretty please post more "alike".
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member apcalculus's Avatar
    Joined
    Apr 2009
    From
    Boston
    Posts
    293
    Quote Originally Posted by courteous View Post
    Are these below a "standard" (i.e. not-obscure) piece one can see in textbooks:

    n_{(r)}=\frac{n^{(r)}}{r!} [ n_{(3)}=\frac{n(n-1)(n-2)}{3!}] and n_{r}=\frac{n^r}{r!}

    ( n!!, I presume, is "standard".)

    Pretty please post more "alike".
    The factorial notation is "standard", sure. Sorry, I may be missing the point here. Are you asking if this notation is typical?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Joined
    Oct 2009
    Posts
    5,517
    Thanks
    771
    I am not sure I've seen the subscript and superscript notation.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,605
    Thanks
    1574
    Awards
    1
    Quote Originally Posted by emakarov View Post
    I am not sure I've seen the subscript and superscript notation.
    I definitely agree with that.

    It appears to me as if the is a combination of the standard usage of permutations and factorials.
    By that I mean _n\mathcal{P}_j=\frac{n!}{(n-j)!} so that _{10}\mathcal{P}_3=(10)(9)(7) .

    So that n_{(r)}=\frac{_n\mathcal{P}_r }{r!}.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 2
    Last Post: March 10th 2011, 01:39 PM
  2. Standard Form/Scientific Notation Question.
    Posted in the Statistics Forum
    Replies: 2
    Last Post: December 22nd 2010, 05:25 AM
  3. Replies: 1
    Last Post: August 26th 2009, 12:40 PM
  4. Replies: 3
    Last Post: January 28th 2009, 01:04 AM
  5. standard form help with scientific notation
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 29th 2006, 04:10 AM

Search Tags


/mathhelpforum @mathhelpforum