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    Evaluate the quantities:
    \displaystyle \binom{100}{99}
    I did this: \frac{100!}{99!(100-99)!}
    = \frac{100!}{99! \times 1!}

    But when I type that in the calculator, I get math error :/ I checked the answer at the back of the book and it says its 100, what am I doing wrong? :/
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    (Original post by Nkhan)
    Evaluate the quantities:
    \displaystyle \binom{100}{99}
    I did this: \frac{100!}{99!(100-99)!}
    = \frac{100!}{99! \times 1!}

    But when I type that in the calculator, I get math error :/ I checked the answer at the back of the book and it says its 100, what am I doing wrong? :/
    It is impossible for a calculator to calcualate 100 and 99!
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    Think what a factorial is.

    100! = 100x99x98...x3x2x1
    99! = 99x98x97.....x3x2x1

    If you think about what cancels here then that'll help you.
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    (Original post by jonathan3909)
    It is impossible for a calculator to calcualate 100 and 99!
    99! is a factor of 100!, so just divide one by the other.

    Edit: whoops, sorry for quoting the wrong person.
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    (Original post by Nkhan)
    Evaluate the quantities:
    \displaystyle \binom{100}{99}
    I did this: \frac{100!}{99!(100-99)!}
    = \frac{100!}{99! \times 1!}

    But when I type that in the calculator, I get math error :/ I checked the answer at the back of the book and it says its 100, what am I doing wrong? :/
    Or think of

    \displaystyle \binom{10}{9}

    =\frac {3628,800}{362880} = 10

    so \displaystyle \binom{100}{99} = 100
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    Lol I just remembered I can always use the nCr button on the calculator to quickly give me the answer!
    But thanks guys
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    (Original post by Nkhan)
    Lol I just remembered I can always use the nCr button on the calculator to quickly give me the answer!
    But thanks guys
    But plugging such a simple thing into a calculator won't reinforce your understanding...
 
 
 
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