1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Log equations

  1. Apr 23, 2007 #1
    1. The problem statement, all variables and given/known data

    solve:Log(subscript 5) X = 1/2log(subscript 5) 25

    2. Relevant equations

    3. The attempt at a solution[/
    Log(subscript 5) X = 1/2log(subscript 5) 25
    --------------- ---------------------
    Log(subscript 5) Log(subscript 5)

    Then they cancel out and I got X = 1/2Log(subscript 5) 25
    Log(subscript 5)

    That's what I got but I'm not sure if its right. Please help

    It looks wierd but i hope you understand what i'm trying to show you.
  2. jcsd
  3. Apr 23, 2007 #2
    It doesn't work that way!!

    [tex] log_5 x = (1/2)(log_5 25) [/tex]
    [tex] log_5 x = (1/2) 2 [/tex]
    [tex] log_5 x = 1 [/tex]

    Please learn the basics and stuff... it will help!
  4. Apr 23, 2007 #3


    User Avatar
    Science Advisor

    I would have done it a slightly different way:
    [tex]log_5(X)= \frac{1}{2}log_5(25)[/tex]
    [tex]log_5(X)= log_5(25^{\frac{1}{2}})[/tex]
    [tex]log_5(X)= log_5(5)[/tex]
    Now it should be easy to see what X is.
  5. Apr 23, 2007 #4
    Learn the basics yourself, you got it wrong!!!!!! jk
  6. Apr 24, 2007 #5


    User Avatar
    Science Advisor

    No, while his statement about learning the basics is a little harsh (though true), his calculation is exactly correct. log5(25)= 2 so (1/2)log5(25)= 1. log5(x)= 1 so x= 1.

    You may need to review yourself!
  7. Apr 24, 2007 #6
    well in that case im really sorry! But its not like i meant it in a hatefl way. Sorry once again.:frown:
  8. Apr 24, 2007 #7


    User Avatar
    Science Advisor

    I didn't think you did. But be careful, in the future, about telling someone else he is wrong. Especially without explaining exactly HOW it is wrong!

    I've started, many times, to tell someone he was wrong, and while writing out exactly WHY he was wrong said "oops" and kept my mouth shut!
  9. Apr 24, 2007 #8
    Speaking of "oops", I'm sure you meant x=5 (as you had a couple posts before.)
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Log equations
  1. Log equations (Replies: 3)

  2. This log equation (Replies: 4)

  3. Log Equation (Replies: 2)

  4. Log Equation (Replies: 6)