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Math Help - tough logarithmic equation

  1. #1
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    tough logarithmic equation

    This problem so far seems impossible,

    3x^2=lnx

    so far I have e^(3x^2) =x

    and I can't really move forward from there.
    any suggestions?
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  2. #2
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    Re: tough logarithmic equation

    It can't be solved exactly. Use a numerical method and/or technology to get an approximate answer.
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  3. #3
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    Re: tough logarithmic equation

    There is not going to be any "algebraic" solution to that equation. That is generally true of equations that involve x both inside and outside a transcendental function.
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  4. #4
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    Re: tough logarithmic equation

    Right so I can have e^(3x^2)-x = 0
    and guess values which get me closer to 0 till I get the accuracy desired.

    Thanks
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  5. #5
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    Re: tough logarithmic equation

    Quote Originally Posted by elieh View Post
    Right so I can have e^(3x^2)-x = 0
    and guess values which get me closer to 0 till I get the accuracy desired.

    Thanks
    Pretty much although don't forget that x > 0. If you plot the graphs you will see that they never intersect and so there are no solutions
    Last edited by e^(i*pi); June 15th 2011 at 03:33 AM. Reason: editing out a mistake
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