Results 1 to 3 of 3

Math Help - Logarithm proofs

  1. #1
    Newbie
    Joined
    May 2007
    Posts
    4

    Logarithm proofs

    Can anyone help with these proofs?

    Prove the following formulas for changing from one base to another:
    a) log_b x = (log_b a)(log_a x)

    b) log_b x = (log_a x)/(log_a b)

    Thank so much
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Bar0n janvdl's Avatar
    Joined
    Apr 2007
    From
    South Africa
    Posts
    1,630
    Thanks
    6
    Quote Originally Posted by Percent09 View Post
    Can anyone help with these proofs?

    Prove the following formulas for changing from one base to another:
    a) log_b x = (log_b a)(log_a x)

    b) log_b x = (log_a x)/(log_a b)

    Thank so much
    Log_a x = P
    log_b x = Q
    log_b a = R

    A^P = b^Q = x

    (b^R)^P = b^Q
    b^RP = b^Q
    RP = Q
    P = Q/R

    log_a x = (log_b x / log_b a)

    Just modify it to suit your question.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Bar0n janvdl's Avatar
    Joined
    Apr 2007
    From
    South Africa
    Posts
    1,630
    Thanks
    6
    I cant seem to find (a) in my maths book...

    Could you just double check your post?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 3
    Last Post: July 18th 2011, 07:04 AM
  2. Logarithm help, please
    Posted in the Algebra Forum
    Replies: 5
    Last Post: March 15th 2010, 05:27 PM
  3. Logarithm help
    Posted in the Pre-Calculus Forum
    Replies: 3
    Last Post: January 14th 2008, 02:54 PM
  4. Logarithm - please help
    Posted in the Algebra Forum
    Replies: 2
    Last Post: October 11th 2007, 03:57 AM
  5. Replies: 3
    Last Post: October 6th 2007, 02:01 PM

Search Tags


/mathhelpforum @mathhelpforum