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Math Help - Please help! After the union, A u B, A = [-3, 8), B = (6,8]

  1. #1
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    Please help! After the union, A u B, A = [-3, 8), B = (6,8]

    A = [-3, 8)
    B = (6,8]

    So A u B is?
    Really confused about it, can you please help?
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  2. #2
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    Re: Please help! After the union, A u B, A = [-3, 8), B = (6,8]

    Quote Originally Posted by adamb View Post
    A = [-3, 8)
    B = (6,8] So A u B is?
    Really confused about it, can you please help?
    How can you possibly be confused? Do you know the definitions?
    $A\cap B= (6,8)$ WHY?
    So $A\cup B=~?$
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  3. #3
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    Re: Please help! After the union, A u B, A = [-3, 8), B = (6,8]

    A u B = (-3,6,8)
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    Re: Please help! After the union, A u B, A = [-3, 8), B = (6,8]

    Quote Originally Posted by adamb View Post
    A u B = (-3,6,8)
    Can you tell us why you do not even understand the notation before posting a question?
    I want to think that you are not an internet troll. This kind of ignorance point to an otherwise conclusion.

    Do you know how the set $(3,6)$ is even defined?
    Do you know what union means?
    Do you have any idea what any of this is about?

    If not, then you are a troll. Please prove us wrong.
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  5. #5
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    Re: Please help! After the union, A u B, A = [-3, 8), B = (6,8]

    Im not trolling anyone here. I understand that A = [-3, 8) and B = (6, 8]
    Im wondering since the notation () and [] are being used does this mean the set
    A contains -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7
    and
    B contains 7, 8
    so A u B is = 7?
    is this correct?
    or does A just contain [-3, 8) -3 and 8 and B (6, 8] just 6 and 8?
    so A u B is = (-3, 6, 8)?
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  6. #6
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    Re: Please help! After the union, A u B, A = [-3, 8), B = (6,8]

    Quote Originally Posted by adamb View Post
    Im not trolling anyone here. I understand that A = [-3, 8) and B = (6, 8]
    Im wondering since the notation () and [] are being used does this mean the set
    A contains -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7
    and
    B contains 7, 8
    so A u B is = 7?
    is this correct?
    or does A just contain [-3, 8) -3 and 8 and B (6, 8] just 6 and 8?
    so A u B is = (-3, 6, 8)?
    Something you have to understand is that [-3,8), for example, stands for all the real numbers between -3 and 8, including -3, not including 8. It's not just the integers.
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  7. #7
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    Re: Please help! After the union, A u B, A = [-3, 8), B = (6,8]

    So you want the union of A = the set of all real numbers between -3 and 8, including -3 but not 8, and B = the set of all real numbers between 6 and 8, including 8 but not 6.

    The union is (by definition) the set of all real numbers in either A or B.

    Now is it easier to see the solution?

    - Hollywood
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