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Natural Log

  1. Dec 1, 2009 #1
    I have the following function:

    y= (sqrt(8x^4-5)) / (x-1)

    take the natural log of both sides:

    1) ln y= ln (sqrt( 8x^4-5) - ln (x-1)


    2) ln y= 1/2 ln(8x^4-5) - ln (x-1)

    Which one is correct?

    I know when i take the natural log of a/b its ln(a)- ln(b)... but also when i take the natural log of a^q its qln(a)...does that apply in this situation also or is it just ln(a)- ln(b)?
  2. jcsd
  3. Dec 1, 2009 #2
    The second would would be the correct option.
  4. Dec 1, 2009 #3
    ok i thought so...thanks!
  5. Dec 1, 2009 #4


    Staff: Mentor

    They're both correct. ln (sqrt( 8x^4-5)) = ln (8x^4 - 5)1/2 = (1/2) ln(8x^4 - 5)
  6. Dec 2, 2009 #5


    User Avatar
    Science Advisor

    Both are correct. The second is simpler and more likely to be accepted as the "correct" way.
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