Results 1 to 9 of 9

Math Help - Functions involving powers of logarithms

  1. #1
    Newbie
    Joined
    Aug 2009
    Posts
    5

    Arrow Functions involving powers of logarithms

    Please see attachment. Thank you.
    Attached Files Attached Files
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,419
    Thanks
    1330
    You are apparently expected to know the "law of logarithms", log(a^b)= b log(a). Here a= |x| and b= x.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Aug 2009
    Posts
    5

    reply to HallsofIvy

    Hi! I quite know the rule you are referring to. The problem is that the two functions do not seem to be the same.
    Try and plot them using a calculator. You'll get two different graphs! Thank you for your help anyway.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by sanders47 View Post
    Please see attachment. Thank you.
    In future please type the question rather than attaching it. The basic latex required for the job is not difficult to learn.

    By \ln^2 |x|^x do you mean (\ln |x|^x)^2 ? In which case the result given by the book is wrong.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Aug 2009
    Posts
    5

    reply to mr. Fantastic

    The basic question is what does the book mean and not
    what I mean.
    I attached my question because:

    • I'm a new member and I'm not familiar with latex;
    • It was important to show the way the function is written in the book
    Thanks.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by sanders47 View Post
    The basic question is what does the book mean and not
    what I mean.
    I attached my question because:

    • I'm a new member and I'm not familiar with latex;
    • It was important to show the way the function is written in the book
    Thanks.
    If you cannot provide the clarification I requested then I don't see how further progress can be made. The meaning I suggested for the notation is a reasonable one, in which case, as I said before, the book is wrong.
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Newbie
    Joined
    Aug 2009
    Posts
    5

    Reply to Mr. Fantastic

    Thank you very much, Mr. Fantastic for the answer.
    Of course I can only provide the text of the function, not being the author myself. Can you think of a possible misprint? In the case, what could have been the correct text? I thank you again for your help
    Follow Math Help Forum on Facebook and Google+

  8. #8
    MHF Contributor
    Joined
    Nov 2008
    From
    France
    Posts
    1,458
    \ln^2 |x|^x = (\ln |x|^x)^2 = (x \ln |x|)^2 = x^2 \:\ln^2 |x|
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Newbie
    Joined
    Aug 2009
    Posts
    5

    reply to running-gag

    Thank you! Maybe, then, that the misprint was a x^2 instead of x.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. equation involving addition of powers
    Posted in the Algebra Forum
    Replies: 3
    Last Post: November 28th 2011, 08:56 PM
  2. Simplifying quotients involving powers of e
    Posted in the Algebra Forum
    Replies: 4
    Last Post: August 14th 2011, 08:27 AM
  3. [SOLVED] Integrals Involving Powers of Trig Functions.
    Posted in the Calculus Forum
    Replies: 2
    Last Post: October 28th 2010, 12:26 AM
  4. [SOLVED] Inequality involving added powers
    Posted in the Differential Geometry Forum
    Replies: 1
    Last Post: September 29th 2010, 12:10 PM
  5. Arithmetic involving powers.
    Posted in the Algebra Forum
    Replies: 1
    Last Post: May 18th 2010, 09:20 PM

Search Tags


/mathhelpforum @mathhelpforum