1. Not finding help here? Sign up for a free 30min 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!

Solve log(x) + log(x+3) = 1

  1. Nov 22, 2008 #1
    1. The problem statement, all variables and given/known data

    logx+log(x+3)=1

    2. Relevant equations



    3. The attempt at a solution

    Ive tried to put it in solve so i know x=2

    i think i have to, hmm i dont know if its called differantiate in english but i dont know how to differantiate log.


    Edit: this is what ive tried after differantiating

    1/x+1/x=1
    that means it must be 2 since 2 halfs give 1
     
    Last edited: Nov 22, 2008
  2. jcsd
  3. Nov 22, 2008 #2

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Re: logx+log(x+3)

    Welcome to Physics Forums.

    I'm guessing that you're trying to solve for equation to find x?
     
  4. Nov 22, 2008 #3
    Re: logx+log(x+3)

    yes, sry for my bad explaining of my problem
     
  5. Nov 22, 2008 #4

    Hootenanny

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Re: logx+log(x+3)

    No problem.

    When attempting to solve equations, usually the best thing to do is to collect all the terms you want together. So can you combine the two log terms into a single logarithm?
     
  6. Nov 22, 2008 #5

    Mark44

    Staff: Mentor

    Re: logx+log(x+3)

    This problem has nothing to do with differentiation. All you need to know are the properties of logarithms and how to factor quadratics.
     
  7. Feb 5, 2011 #6
    Re: logx+log(x+3)

    I know this is an old post but incase people find it in the future:

    rule 1)
    logbx + logby = logbxy

    rule 2)
    x (x + a) = x2 + ax

    rule 3)
    solving quadratic equations
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Solve log(x) + log(x+3) = 1
  1. F'(x) of log x (Replies: 5)

Loading...