Results 1 to 6 of 6

Math Help - anybody good with logs??

  1. #1
    Junior Member
    Joined
    Jan 2007
    Posts
    36

    anybody good with logs??

    i have log_L (1-r)

    with L = 2 and r = 0.02

    does any1 know how to put log to the base into a calculator or any other way of calculating it?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Eater of Worlds
    galactus's Avatar
    Joined
    Jul 2006
    From
    Chaneysville, PA
    Posts
    3,001
    Thanks
    1
    You appear to have log_{2}(1-0.02)=log_{2}(0.98)

    When entering into a calculator, use the change of base formula.

    log_{b}(u)=\frac{log_{a}(u)}{log_{a}(b)}

    In this case, \frac{log(0.98)}{log(2)}\approx{-0.02914}

    Do not confuse the change of base formula with the quotient rule for logs.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Jan 2007
    Posts
    36
    Quote Originally Posted by galactus View Post
    You appear to have log_{2}(1-0.02)=log_{2}(0.98)

    When entering into a calculator, use the change of base formula.

    log_{b}(u)=\frac{log_{a}(u)}{log_{a}(b)}

    In this case, \frac{log(0.98)}{log(2)}\approx{-0.02914}

    Do not confuse the change of base formula with the quotient rule for logs.

    having Tr = 1/1-log_L(1-r)

    with L = 2 and r = 0.02

    i get this to be equal to 0.97168 and i know the answer is approx 100 so should my answer be multiplied by 100?? is this the rite procedure?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Eater of Worlds
    galactus's Avatar
    Joined
    Jul 2006
    From
    Chaneysville, PA
    Posts
    3,001
    Thanks
    1
    No. Where does the 100 come from?.

    log_{2}(1267650600228229401496703205376)=100
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Jan 2007
    Posts
    36
    the answer has to be 100 years its a return period for a flood
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by question View Post
    the answer has to be 100 years its a return period for a flood
    Perhaps you should post the actual question you are trying to answer.

    RonL
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 9
    Last Post: February 22nd 2011, 06:39 PM
  2. good books forbiing really good at math and physics
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: August 22nd 2009, 04:26 PM
  3. Dealing with Logs and Natural Logs
    Posted in the Advanced Algebra Forum
    Replies: 0
    Last Post: April 14th 2008, 07:18 AM
  4. several questions-logs/natural logs
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: November 12th 2007, 09:58 PM

Search Tags


/mathhelpforum @mathhelpforum