Results 1 to 4 of 4

Math Help - Fairly basic natural log query (C3)

  1. #1
    Newbie
    Joined
    Aug 2012
    From
    London
    Posts
    22

    Fairly basic natural log query (C3)

    I'm fairly sure this is the correct answer:

    e^-3x = 27

    -3x = ln27

    x = ln27 / -3

    However, in the answers section of my textbook, the given value for the answer is -ln3.
    Please can someone help explain how the two answers are related and how to obtain such answer from the equation. I am only familiar with the above method.
    Thanks!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,969
    Thanks
    1788
    Awards
    1

    Re: Fairly basic natural log query (C3)

    Quote Originally Posted by DonGorgon View Post
    I'm fairly sure this is the correct answer:
    e^-3x = 27
    -3x = ln27
    x = ln27 / -3
    However, in the answers section of my textbook, the given value for the answer is -ln3.
    \ln(27)=\ln(3^3)=3\ln(3)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Aug 2012
    From
    London
    Posts
    22

    Re: Fairly basic natural log query (C3)

    Quote Originally Posted by Plato View Post
    \ln(27)=\ln(3^3)=3\ln(3)
    Cheers, thought as much. However is there any different steps to take, or is it just as you mentioned?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,969
    Thanks
    1788
    Awards
    1

    Re: Fairly basic natural log query (C3)

    Quote Originally Posted by DonGorgon View Post
    Cheers, thought as much. However is there any different steps to take, or is it just as you mentioned?
    You could do
    e^{-3x}=27
    e^{-x}=3 (cube root).
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Fairly basic natural logs question
    Posted in the Calculus Forum
    Replies: 3
    Last Post: September 3rd 2012, 04:45 PM
  2. Fairly simple integration by parts query
    Posted in the Calculus Forum
    Replies: 1
    Last Post: October 22nd 2011, 06:24 PM
  3. Intergration Question (fairly basic)
    Posted in the Calculus Forum
    Replies: 4
    Last Post: May 18th 2009, 01:30 AM
  4. Stuck, it's fairly basic, please help!
    Posted in the Algebra Forum
    Replies: 7
    Last Post: October 10th 2008, 04:55 PM
  5. Matrix Algebra - fairly basic
    Posted in the Advanced Algebra Forum
    Replies: 9
    Last Post: October 14th 2007, 12:00 PM

Search Tags


/mathhelpforum @mathhelpforum