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    Factorials, Combinations and Permutations Calculators

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    تاريخ التسجيل : 16/02/2011

    Factorials, Combinations and Permutations Calculators

    مُساهمة  Admin في الإثنين فبراير 21, 2011 10:14 am

    Factorials, Combinations and Permutations Calculators



    Factorials


    A factorial is denoted using an ! symbol. For example...




    4! = 4 × 3 × 2 × 1 = 24





    10! = 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1 = 3,628,800





    3! = 3 × 2 × 1 = 6



    As you can see, 10!, pronounced 10 factorial, is a large number. What about 20! or 100!?


    Most calculators including the TI 's series will only calculate factorials up to 69!




    69! = 1.711224524 E 98 = 107,112,245,240,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
    000,000,000,000,000,000,000,000,000



    Other important facts....


    n! = n(n - 1)(n -2) · · ·1 where n is an integer greater than 0


    1! = 1
    0! = 1
    ( -2)! is undefined



    Example


    There are n! distinct arrangement of n distinct objects. If 3 people race, there are 3! = 6 different outcomes. If you want to arrange 6 different books on a shelf, there are 6! = 720 different arrangements.


    Permutations
    Notice P(7,4) = 840
    but P(7,3) = 210




    Combinations

    Notice C(7,4) = C(7,3) = 35



    Try this calculator... for C(n,r)








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    Factorials, Combinations and Permutations Calculators

      الوقت/التاريخ الآن هو الإثنين أكتوبر 23, 2017 9:47 pm