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Math Help - Summation Notation Help

  1. #1
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    Summation Notation Help

    Hey guys!

    I have no idea about this stuff and haven't really seen it before, any help is appreciated because I'm really struggling; thanks!

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  2. #2
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    Re: Summation Notation Help

    The sigma notation \displaystyle \sum_{i = 1}^N { \left( X_i - \bar{X} \right)} gives us a shorthand for a sum with a counter i going from 1 to N, so it translates to \displaystyle \left( X_1 - \bar{X} \right) + \left( X_2 + \bar{X} \right) + \left( X_3 + \bar{X} \right) + \dots + \left( X_N + \bar{X} \right) .

    Similarly, the pi notation \displaystyle \prod _{j = 0}^{x-1} {\left( x - j \right) } gives us a shorthand for a product with a counter j going from 0 to x - 1. So it translates to \displaystyle \left( x - 0 \right) \left( x - 1 \right) \left( x - 2 \right) \dots \left[ x - \left( x - 1 \right) \right] = x \left( x - 1 \right) \left( x - 2 \right) \dots 1 .
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  3. #3
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    Re: Summation Notation Help

    Quote Originally Posted by Prove It View Post
    Similarly, the pi notation \displaystyle \prod _{j = 0}^{x-1} {\left( x - j \right) } gives us a shorthand for a product with a counter j going from 0 to x - 1. So it translates to \displaystyle \left( x - 0 \right) \left( x - 1 \right) \left( x - 2 \right) \dots \left[ x - \left( x - 1 \right) \right] = x \left( x - 1 \right) \left( x - 2 \right) \dots 1 .
    What are you getting at with this?

    I understand you explanation of part (a), (thank you so much!), but I don't really understand how this helps me out.
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  4. #4
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    Re: Summation Notation Help

    bump
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