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!

Homework Help: Logs homework

  1. Feb 6, 2008 #1
    1. The problem statement, all variables and given/known data

    [tex]ln(6xy)-3ln(2y)-1/3 ln x + ln 20[/tex]

    The attempt at a solution

    I can get to [tex]ln\left(\frac{120xy}{8y^3x^1^/^3}\right)[/tex]

    And then to

    [tex]ln\left(\frac{120}{8}*\frac{x}{x^1^/^3}*\frac{y}{y^3}\right)[/tex]

    But then I am supposed to do something to get to [tex]ln\left(\frac{15yx^2^/^3}{y^2}\right)[/tex]

    What do I do? how does [tex]\frac{x}{x^1^/^3}[/tex] turn into [tex]x^2^/^3[/tex] and how does [tex]\frac{y}{y^3}[/tex] turn into [tex]y^2[/tex] ?
     
  2. jcsd
  3. Feb 6, 2008 #2
    well x^p/x^q =x^(p-q)

    same for y
     
  4. Feb 6, 2008 #3
    o. simple. Thanks :)
     
  5. Feb 7, 2008 #4

    HallsofIvy

    User Avatar
    Science Advisor

    Or
    [tex]\frac{y}{y^3}= \frac{y}{y\cdot y\cdot y}= \frac{1}{y\cdot y}= \frac{1}{y^2}[/tex]
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook