Results 1 to 4 of 4

Math Help - log problems

  1. #1
    Junior Member
    Joined
    Jan 2008
    Posts
    69

    log problems

    logquest.jpg - Image - Photobucket - Video and Image Hosting

    Very simple, and very easy. I am just not sure why they say 10/3 as they answer in the answer book... When I look at previous questions, to me, it would seem to be 3/3, and 1. My mistake or theirs?
    Last edited by Slipery; January 7th 2009 at 02:13 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Dec 2008
    From
    Scotland
    Posts
    901
    Quote Originally Posted by Slipery View Post
    logquest.jpg - Image - Photobucket - Video and Image Hosting

    Very simple, and very easy. I am just not sure why they say 10/3 as they answer in the answer book... When I look at previous questions, to me, it would seem to be 3/3, and 1. My mistake or theirs?
    No, when you multiply two things, you ADD their exponents, not multiply them.

     \log_{10}{|10^3 \times 10^{\frac{1}{3}}|}

     \log_{10}{|10^3|} + \log_{10}{|10^{\frac{1}{3}}|}

     3 + \frac{1}{3}

     \frac{9}{3} + \frac{1}{3} = \frac{10}{3}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jan 2008
    Posts
    69
    Ahhhh, no wonder. Thats a pretty absent-minded mistake by myself, Thanks
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member

    Joined
    May 2006
    From
    Lexington, MA (USA)
    Posts
    11,682
    Thanks
    614
    Hello, Slipery!

    You forgot one of the rules of logs (or exponents)



    \log\left(1000\sqrt[3]{10}\right)

    We have: . \log\left(1000\sqrt[3]{10}\right) \:=\:\log\left(10^3\cdot10^{\frac{1}{3}}\right) . = \;\log\left(10^{3+\frac{1}{3}}\right) \;=\;\log\left(10^{\frac{10}{3}}\right) \quad\hdots\;\text{ etc.}


    We have: . \log\left(10^3\cdot10{\frac{1}{3}}\right) \;=\;\log\left(10^3\right ) + \log\left(10^{\frac{1}{3}}\right) \quad\hdots\;\text{ etc.}


    Got it?

    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: October 3rd 2011, 05:35 AM
  2. binomial problems/normal problems
    Posted in the Statistics Forum
    Replies: 1
    Last Post: October 19th 2010, 11:46 PM
  3. binomial problems as normal problems
    Posted in the Statistics Forum
    Replies: 1
    Last Post: October 19th 2010, 11:41 PM
  4. Problems with integration word problems
    Posted in the Calculus Forum
    Replies: 5
    Last Post: April 25th 2010, 05:39 PM
  5. Help thease problems problems
    Posted in the Geometry Forum
    Replies: 2
    Last Post: April 1st 2008, 11:03 AM

Search Tags


/mathhelpforum @mathhelpforum