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Math Help - Radicals, Radical functions and rational exponents Help please

  1. #16
    MHF Contributor Quick's Avatar
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    7.96(2.4494 - 2)
    Malaygoel, it's not that your wrong it's just that the answer needs to be in simplest radical form, otherwise it would've taken maybe 4 seconds to do.

    Also,
    \frac{15.92}{2} (\sqrt{ 6} - \sqrt{ 4})=<br />
\sqrt{3.99}\sqrt{ 6} - \sqrt{3.99}\sqrt{ 4}
    where did you get  \sqrt{3.99} ?
    Remember:  \frac{15.92}{2}=7.96=\sqrt{63.3616}
    Last edited by Quick; June 5th 2006 at 02:48 AM.
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  2. #17
    MHF Contributor Quick's Avatar
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    √23.94 - √15.96 = √7.98/2 = 3.9
    You've done two things wrong in your expression. First off if you want to turn 15.92 into a radical number you need to remember this rule:
     x = \sqrt{x^2}
    It doesn't equal this:
     x \neq \sqrt{x} \neq  \sqrt{\sqrt{x}}

    and you also subtracted radicals incorrectly, remember these rules:
     \sqrt{6}\pm\sqrt{4} \neq \sqrt{6\pm4}
     \sqrt{6}\sqrt{4} = \sqrt{6\cdot4}
    Last edited by Quick; June 5th 2006 at 03:14 AM.
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  3. #18
    MHF Contributor Quick's Avatar
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    The Answer

    I figured it out.
    Continuing on my work:

     \left(4\sqrt{6}-8\right)\left(\sqrt{3.9601}\right)
     4\sqrt{6}\sqrt{3.9601}-8\sqrt{3.9601}
     4\sqrt{6\cdot3.9601}-\sqrt{64}\sqrt{3.9601}
     4\sqrt{23.7606}-\sqrt{64\cdot3.9601}
     4\sqrt{23.7606}-\sqrt{253.4464}
     4\sqrt{4\cdot7.9202}-15.92
     4\sqrt{4}\sqrt{7.9202}-15.92
     4\cdot2\sqrt{7.9202}-15.92
     8\sqrt{7.9202}-15.92 \approx 3.6

    Looking back, I did more work than was needed at the beginning.
    (and it seems I have triple posted)
    Last edited by Quick; June 5th 2006 at 03:31 AM.
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  4. #19
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    Wow

    Thanks to you both for that information. I stayed on it until about midnight last night and had had enough of that problem. I keep trying no matter if I get the problem wrong but sometimes it easier seeing someone else show where you've gone wrong. Thanks you very much!!
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  5. #20
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    The 3.99

    Quick,

    I took the square root of 15.92 to come up with the 3.99 thinking I could do the problem that way. I now know that was a wrong maneuver. Thanks again.
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