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Math Help - Logarithm Easy Question Help!

  1. #1
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    Logarithm Easy Question Help!

    If lnx^2= 3x, Find the Value of X.

    I am missing a major property. Could someone help me 0ut on this one?!

    Thank you
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  2. #2
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by r2d2 View Post
    If lnx^2= 3x, Find the Value of X.

    I am missing a major property. Could someone help me 0ut on this one?!

    Thank you
    Do you mean ln(x^2) or [ln(x)]^2

    Either way you will need to use an iterative solution
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  3. #3
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    I mean ln(x^2)
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  4. #4
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    Quote Originally Posted by r2d2 View Post
    I mean ln(x^2)
    There are actually no real (and possibly no complex) solutions for this equation because the two lines do not meet - see the attached graph
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  5. #5
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    well I have the answer is equal to e^3/2. Or e^(3/2)
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  6. #6
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    Quote Originally Posted by r2d2 View Post
    well I have the answer is equal to e^3/2. Or e^(3/2)
    If you sub that back into the original equation you do not get 0

    <br />
2ln(e^{1.5}) \neq 3e^{1.5}<br />
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  7. #7
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    Ok I must have copied the problem wrong.

    Here it is: not simplified.


    -x-2x+2xlnx=0

    Solve for x.
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  8. #8
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    Quote Originally Posted by r2d2 View Post
    Ok I must have copied the problem wrong.

    Here it is: not simplified.


    -x-2x+2xlnx=0

    Solve for x.

    -x - 2x + 2x\ln{x} = 0

    -3x + 2x\ln{x} = 0

    x(-3 + 2\ln{x}) = 0

    x = 0 is an invalid solution because of domain reasons.

    \ln{x} = \frac{3}{2}

    x = e^{\frac{3}{2}}
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  9. #9
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    i also got e^(3/2), you just copied it down wrong the first time,
    so ur correct
    as;
    -x-2x+2xlnx=0
    -3x+2xlnx=0
    2xlnx=3x
    lnx=3x/2x
    lnx=3/2
    x=e^(3/2)
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  10. #10
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    Great! Thank you everybody
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