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    what does n! mean and how would you simplify

    n!/2(n-2)!

    steps would be appreciated
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    n! means n factorial, so it means n multiplied by n-1 multiplied by n-2 etc etc all the way down to one

    e.g. 10! = 10x9x8x7x6x5x4x3x2x1
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    (Original post by Triple D)
    what does n! mean and how would you simplify

    n!/2(n-2)!

    steps would be appreciated

    Im guessing it simplifies to n(n-1)/2 although I seldom deal with factorials.
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    (Original post by Triple D)
    what does n! mean and how would you simplify

    n!/2(n-2)!

    steps would be appreciated
    2(n-2)! = 2(n-2)*(n-3)*(n-4)*...*3*2*1
    2(n-2)! = (2n-4)*(2n-6)*(2n-8)*...*3*2*1

    But

    n*(n-1)*(n-2)*(n-3)*...*3*2*1
    -----------------------------
    (n-2)*(n-3)*(n-4)*...*3*2*1

    Cancels down to:

    n*(n-1) = n^2 - n

    Add the half back in..

    So n!/2(n-2)! = (n²-n)/2
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    (Original post by Triple D)
    what does n! mean and how would you simplify

    n!/2(n-2)!

    steps would be appreciated
    n!=n(n-1)(n-2).....1
    (n-2)!=(n-2)(n-3)...1

    so u get 1/2 *n(n-1)(n-2)..../(n-2)....

    so all the terms cancel except n(n-1) and 1/2
    so u get n(n-1)/2
    which is wot ralfskini put
 
 
 
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