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    So I have this question:


    For b, I got p = 3-2√2 and 3+2√2. The mark scheme says the answer is:

    p<3-2√2 or p>3+2√2

    How do I know whether to put "or" or just write it like: 3+2√2 < p < 3-2√2 ?
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    (Original post by кяя)
    So I have this question:

    For b, I got p = 3-2√2 and 3+2√2. The mark scheme says the answer is:

    p<3-2√2 or p>3+2√2

    How do I know whether to put "or" or just write it like: 3+2√2 < p < 3-2√2 ?
    You sketch the graph of p^2 - 6p +1 &gt; 0. Always sketch the graph, it doesn't need to be elaborate, just a U if the number in front of p^2 is positive and an upside down u it's negative.

    Label the roots (where it cuts the axis) as your values.



    Then you know that you want the graph to be >0, that is, above the p-axis. That's precisely the region that >second root and <first root.

    Had it asked you for p^2 - 6p + 12 < 0, then you would want the region where the graph is under the x-axis which is in between the two roots, so 3 - sqrt(blah) < p < blah
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    (Original post by Zacken)
    so 3 - sqrt(blah) < p < blah
    :lol:
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    (Original post by Alexion)
    :lol:
    I got lazy towards the end.
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    (Original post by кяя)

    How do I know whether to put "or" or just write it like: 3+2√2 < p < 3-2√2 ?
    Well the value on the left is greater than the value on the right, so that can't be correct.
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    Oh, I get it now. Thanks guys!! repped
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    (Original post by кяя)
    Oh, I get it now. Thanks guys!! repped
    No problem.
 
 
 
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