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Math Help - help solving for variable

  1. #1
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    help solving for variable

    m = \frac{1}{\sqrt{1-k^2}}

    I need to solve for k. Is this the correct steps?

    \sqrt{1-k^2}m = 1
    \sqrt{1-k^2} = \frac{1}{m}
    \pm(1-k^2) = \frac{1}{m^2}

    But I get stuck here. How would I isolate for k?
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  2. #2
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    Quote Originally Posted by centenial View Post
    m = \frac{1}{\sqrt{1-k^2}}

    I need to solve for k. Is this the correct steps?

    \sqrt{1-k^2}m = 1
    \sqrt{1-k^2} = \frac{1}{m}
    \pm(1-k^2) = \frac{1}{m^2}

    But I get stuck here. How would I isolate for k?
    i hope the ans below can help u
    Attached Thumbnails Attached Thumbnails help solving for variable-untitled.jpg  
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  3. #3
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    Quote Originally Posted by nikk View Post
    i hope the ans below can help u
    Thank you for your quick and helpful reply.

    The one step I don't understand is how you get from

    [\sqrt{1-k^2}]^2 = (\frac{1}{m})^2

    to

    1-k^2 = \frac{1}{m^2}

    I understand that this must be done by the sqrt/power cancelling. But don't i need to add a +- in such a case?

    Thanks for your explanation!
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  4. #4
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    Quote Originally Posted by centenial View Post
    Thank you for your quick and helpful reply.

    The one step I don't understand is how you get from

    [\sqrt{1-k^2}]^2 = (\frac{1}{m})^2

    to

    1-k^2 = \frac{1}{m^2}

    I understand that this must be done by the sqrt/power cancelling. But don't i need to add a +- in such a case?

    Thanks for your explanation!
    You don't need a plus/minus sign because any real number squared is positive (or 0).

    If you were to find m in terms of k you'd need it
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  5. #5
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    Quote Originally Posted by centenial View Post
    Thank you for your quick and helpful reply.

    The one step I don't understand is how you get from

    [\sqrt{1-k^2}]^2 = (\frac{1}{m})^2

    to

    1-k^2 = \frac{1}{m^2}

    I understand that this must be done by the sqrt/power cancelling. But don't i need to add a +- in such a case?

    Thanks for your explanation!
    + or - normally the case as below
    <br />
\sqrt 25 = + - 5<br />

    and not for
    <br />
[\sqrt 25]^2 <br />

    sorry if my explanation,english and latex comman is bad
    Last edited by nikk; March 26th 2010 at 11:54 AM. Reason: spelling
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  6. #6
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    Okay, that makes sense. Thanks so much for your help!
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  7. #7
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    Quote Originally Posted by centenial View Post
    Okay, that makes sense. Thanks so much for your help!
    no problem
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