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Math Help - Solving ln sqrt(x+4) = 1

  1. #1
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    Solving ln sqrt(x+4) = 1

    just one more and im done

    so ln sqrt(x+4) = 1

    = e^1 = sqrt(x+4)...square both sides

    e^2 = x+4
    e^2-4 = x

    now I need to solve by hand in exact form. Is this as far as I can go?
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  2. #2
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    Re: quick question on product rule and equality rule for logs

    Quote Originally Posted by RYdis View Post
    just one more and im done

    so ln sqrt(x+4) = 1

    = e^1 = sqrt(x+4)...square both sides Get rid of that first equals sign

    e^2 = x+4
    e^2-4 = x

    now I need to solve by hand in exact form. Is this as far as I can go?
    Yes, this is the answer in exact form. The only thing you might be able to do is factorise the LHS using Difference of Two Squares...
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    Re: quick question on product rule and equality rule for logs

    Quote Originally Posted by Prove It View Post
    Yes, this is the answer in exact form. The only thing you might be able to do is factorise the LHS using Difference of Two Squares...
    (e-2)(e+2) = x?

    since squares can't be negative..does this leave just e+2 = x instead of
    e+2 = x or e-2 = x. should I just leave as the difference?
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    Re: quick question on product rule and equality rule for logs

    Quote Originally Posted by RYdis View Post
    (e-2)(e+2) = x?

    since squares can't be negative..does this leave just e+2 = x instead of
    e+2 = x or e-2 = x. should I just leave as the difference?
    No, x = (e-2)(e+2). You can't go any further.
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    Re: quick question on product rule and equality rule for logs

    Quote Originally Posted by Prove It View Post
    No, x = (e-2)(e+2). You can't go any further.
    awesome, thanks for help, starting to get it now.
    Last edited by mr fantastic; October 20th 2011 at 04:44 AM. Reason: Moved a new question to a new thread.
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