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Math Help - Subset contained

  1. #1
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    Subset contained

    I have a simple problem. I need to show how one set is contained in another.

    Set A= (x,y) is an element R^2: y>2x+1
    Set B= (x,y) is an element R^2: y>(x+1)^2

    I need to show that set B is contained with set B

    Can anyone help?

    Thx
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  2. #2
    Senior Member BAdhi's Avatar
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    (x+1)^2=x^2+(2x+1)

    if something is larger than (x+1)^2 then it is larger than 2x+1
    Last edited by BAdhi; January 31st 2011 at 05:51 AM. Reason: added description at the end
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  3. #3
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    Thank you, but I need to determine whether set B is contained within set A.

    Maybe I am just having a mental block.

    Can anyone clarify?
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  4. #4
    Senior Member BAdhi's Avatar
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    i don't know whether this method is correct, but just trying, please tell me if i'm making anything wrong

    take any (x,y)\in B

    y>(x+1)^2>2x+1 \implies y>2x+1

    \therefore  (x,y)\in A

    \therefore B \subset A
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