Results 1 to 6 of 6

Math Help - log expressions

  1. #1
    Junior Member
    Joined
    Jan 2010
    Posts
    60

    log expressions

    If log5=a and log36=b, determine an expression for log 6/25 in terms of a and b

    I can get the log5 side, as 2a, but i can't seem to get the other side, is the expression wrong, or am i just confused, i can't seem to get 36log6,
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Jun 2009
    Posts
    806
    Thanks
    4
    Quote Originally Posted by nuckers View Post
    If log5=a and log36=b, determine an expression for log 6/25 in terms of a and b

    I can get the log5 side, as 2a, but i can't seem to get the other side, is the expression wrong, or am i just confused, i can't seem to get 36log6,
    log36 = log(6)^2 = 2log(6) = b.

    So log(6) = .....?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jan 2010
    Posts
    60
    Quote Originally Posted by sa-ri-ga-ma View Post
    log36 = log(6)^2 = 2log(6) = b.

    So log(6) = .....?
    no, i dont understand it, i have to have 36log so b=36
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member
    Joined
    Jun 2009
    Posts
    806
    Thanks
    4
    Quote Originally Posted by nuckers View Post
    no, i dont understand it, i have to have 36log so b=36
    log(6) + log(6) = log(36) = b

    So 2log(6) = b
    Or log(6) = b/2
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor undefined's Avatar
    Joined
    Mar 2010
    From
    Chicago
    Posts
    2,340
    Awards
    1
    log(6/25) = log(6) - log(25)

    Using sa-ri-ga-ma's result, log(6) = b/2

    Now for the other part,

    a = log(5) = (1/2)(2 log(5)) = (1/2)log(25)

    2a = log(25)

    So combining, \log\left(\frac{6}{25}\right) = \frac{b}{2}-2a
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Junior Member
    Joined
    Jan 2010
    Posts
    60
    thanks guys, but i'm just not seeing it, maybe i've just looked at too much math today, maybe a good nights sleep will make it better
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. More expressions
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: March 13th 2010, 02:50 PM
  2. Rational Expressions and Radical Expressions
    Posted in the Algebra Forum
    Replies: 16
    Last Post: July 9th 2009, 10:29 PM
  3. Some expressions
    Posted in the Math Topics Forum
    Replies: 4
    Last Post: October 29th 2008, 12:48 PM
  4. 3 Xor expressions
    Posted in the Discrete Math Forum
    Replies: 5
    Last Post: August 2nd 2007, 11:27 AM
  5. Expressions
    Posted in the Algebra Forum
    Replies: 1
    Last Post: February 1st 2007, 08:28 PM

Search Tags


/mathhelpforum @mathhelpforum