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Math Help - Union and addition of Intervals

  1. #1
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    Union and addition of Intervals

    A=[-1,0)
    B=(0,1]

    Find A U B and A + B (x+y such that x is an element of A and y is an element of B)

    I know how to find the answers of two closed intervals but I'm not sure about intervals that are open and closed. Would the answers be considered compact?

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  2. #2
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    Re: Union and addition of Intervals

    Quote Originally Posted by willywonk View Post
    A=[-1,0) , B=(0,1]
    Find A U B and A + B (x+y such that x is an element of A and y is an element of B)

    I know how to find the answers of two closed intervals but I'm not sure about intervals that are open and closed. Would the answers be considered compact?

    I am not sure exactly notation you are required to use.

    A\cup B=[-1,1]\setminus\{0\}. WHY?

    Edit: I don't understand what happened but part of my reply is missing.

    A+B=(-1,1). But you must explain why.
    Last edited by Plato; January 30th 2013 at 02:04 PM.
    Thanks from willywonk
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  3. #3
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    Re: Union and addition of Intervals

    I don't know about the answers being compact but the sets are not.
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